diff --git a/Marlin/ConfigurationStore.cpp b/Marlin/ConfigurationStore.cpp
index dbbe33a23b..54e69c0134 100644
--- a/Marlin/ConfigurationStore.cpp
+++ b/Marlin/ConfigurationStore.cpp
@@ -116,38 +116,38 @@ void Config_PrintSettings()
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Steps per unit:");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M92 X",axis_steps_per_unit[0]);
-    SERIAL_ECHOPAIR(" Y",axis_steps_per_unit[1]);
-    SERIAL_ECHOPAIR(" Z",axis_steps_per_unit[2]);
-    SERIAL_ECHOPAIR(" E",axis_steps_per_unit[3]);
+    SERIAL_ECHOPAIR("  M92 X",axis_steps_per_unit[X_AXIS]);
+    SERIAL_ECHOPAIR(" Y",axis_steps_per_unit[Y_AXIS]);
+    SERIAL_ECHOPAIR(" Z",axis_steps_per_unit[Z_AXIS]);
+    SERIAL_ECHOPAIR(" E",axis_steps_per_unit[E_AXIS]);
     SERIAL_ECHOLN("");
       
     SERIAL_ECHO_START;
 #ifdef SCARA
 SERIAL_ECHOLNPGM("Scaling factors:");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M365 X",axis_scaling[0]);
-    SERIAL_ECHOPAIR(" Y",axis_scaling[1]);
-    SERIAL_ECHOPAIR(" Z",axis_scaling[2]);
+    SERIAL_ECHOPAIR("  M365 X",axis_scaling[X_AXIS]);
+    SERIAL_ECHOPAIR(" Y",axis_scaling[Y_AXIS]);
+    SERIAL_ECHOPAIR(" Z",axis_scaling[Z_AXIS]);
     SERIAL_ECHOLN("");
       
     SERIAL_ECHO_START;
 #endif
     SERIAL_ECHOLNPGM("Maximum feedrates (mm/s):");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M203 X",max_feedrate[0]);
-    SERIAL_ECHOPAIR(" Y",max_feedrate[1] ); 
-    SERIAL_ECHOPAIR(" Z", max_feedrate[2] ); 
-    SERIAL_ECHOPAIR(" E", max_feedrate[3]);
+    SERIAL_ECHOPAIR("  M203 X", max_feedrate[X_AXIS]);
+    SERIAL_ECHOPAIR(" Y", max_feedrate[Y_AXIS]); 
+    SERIAL_ECHOPAIR(" Z", max_feedrate[Z_AXIS]); 
+    SERIAL_ECHOPAIR(" E", max_feedrate[E_AXIS]);
     SERIAL_ECHOLN("");
 
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Maximum Acceleration (mm/s2):");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M201 X" ,max_acceleration_units_per_sq_second[0] ); 
-    SERIAL_ECHOPAIR(" Y" , max_acceleration_units_per_sq_second[1] ); 
-    SERIAL_ECHOPAIR(" Z" ,max_acceleration_units_per_sq_second[2] );
-    SERIAL_ECHOPAIR(" E" ,max_acceleration_units_per_sq_second[3]);
+    SERIAL_ECHOPAIR("  M201 X" ,max_acceleration_units_per_sq_second[X_AXIS] ); 
+    SERIAL_ECHOPAIR(" Y" , max_acceleration_units_per_sq_second[Y_AXIS] ); 
+    SERIAL_ECHOPAIR(" Z" ,max_acceleration_units_per_sq_second[Z_AXIS] );
+    SERIAL_ECHOPAIR(" E" ,max_acceleration_units_per_sq_second[E_AXIS]);
     SERIAL_ECHOLN("");
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Acceleration: S=acceleration, T=retract acceleration");
@@ -170,17 +170,17 @@ SERIAL_ECHOLNPGM("Scaling factors:");
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Home offset (mm):");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M206 X",add_homing[0] );
-    SERIAL_ECHOPAIR(" Y" ,add_homing[1] );
-    SERIAL_ECHOPAIR(" Z" ,add_homing[2] );
+    SERIAL_ECHOPAIR("  M206 X",add_homing[X_AXIS] );
+    SERIAL_ECHOPAIR(" Y" ,add_homing[Y_AXIS] );
+    SERIAL_ECHOPAIR(" Z" ,add_homing[Z_AXIS] );
     SERIAL_ECHOLN("");
 #ifdef DELTA
     SERIAL_ECHO_START;
     SERIAL_ECHOLNPGM("Endstop adjustement (mm):");
     SERIAL_ECHO_START;
-    SERIAL_ECHOPAIR("  M666 X",endstop_adj[0] );
-    SERIAL_ECHOPAIR(" Y" ,endstop_adj[1] );
-    SERIAL_ECHOPAIR(" Z" ,endstop_adj[2] );
+    SERIAL_ECHOPAIR("  M666 X",endstop_adj[X_AXIS] );
+    SERIAL_ECHOPAIR(" Y" ,endstop_adj[Y_AXIS] );
+    SERIAL_ECHOPAIR(" Z" ,endstop_adj[Z_AXIS] );
 	SERIAL_ECHOLN("");
 	SERIAL_ECHO_START;
 	SERIAL_ECHOLNPGM("Delta settings: L=delta_diagonal_rod, R=delta_radius, S=delta_segments_per_second");
@@ -303,9 +303,9 @@ void Config_ResetDefault()
     max_xy_jerk=DEFAULT_XYJERK;
     max_z_jerk=DEFAULT_ZJERK;
     max_e_jerk=DEFAULT_EJERK;
-    add_homing[0] = add_homing[1] = add_homing[2] = 0;
+    add_homing[X_AXIS] = add_homing[Y_AXIS] = add_homing[Z_AXIS] = 0;
 #ifdef DELTA
-	endstop_adj[0] = endstop_adj[1] = endstop_adj[2] = 0;
+	endstop_adj[X_AXIS] = endstop_adj[Y_AXIS] = endstop_adj[Z_AXIS] = 0;
 	delta_radius= DELTA_RADIUS;
 	delta_diagonal_rod= DELTA_DIAGONAL_ROD;
 	delta_segments_per_second= DELTA_SEGMENTS_PER_SECOND;
diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index d0f988c179..5eebec9736 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -345,8 +345,8 @@
 
   #define D_FILAMENT 2.85
   #define STEPS_MM_E 836
-  #define EXTRUTION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
-  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUTION_AREA)
+  #define EXTRUSION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
+  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUSION_AREA)
 
 #endif // ADVANCE
 
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index bea1db7272..59b291cfe9 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -1537,7 +1537,7 @@ void process_commands()
 		#ifdef SCARA
 		   current_position[X_AXIS]=code_value();
 		#else
-		   current_position[X_AXIS]=code_value()+add_homing[0];
+		   current_position[X_AXIS]=code_value()+add_homing[X_AXIS];
 		#endif
         }
       }
@@ -1547,7 +1547,7 @@ void process_commands()
          #ifdef SCARA
 		   current_position[Y_AXIS]=code_value();
 		#else
-		   current_position[Y_AXIS]=code_value()+add_homing[1];
+		   current_position[Y_AXIS]=code_value()+add_homing[Y_AXIS];
 		#endif
         }
       }
@@ -1612,7 +1612,7 @@ void process_commands()
 
       if(code_seen(axis_codes[Z_AXIS])) {
         if(code_value_long() != 0) {
-          current_position[Z_AXIS]=code_value()+add_homing[2];
+          current_position[Z_AXIS]=code_value()+add_homing[Z_AXIS];
         }
       }
       #ifdef ENABLE_AUTO_BED_LEVELING
@@ -2745,9 +2745,9 @@ Sigma_Exit:
       SERIAL_PROTOCOLLN("");
       
       SERIAL_PROTOCOLPGM("SCARA Cal - Theta:");
-      SERIAL_PROTOCOL(delta[X_AXIS]+add_homing[0]);
+      SERIAL_PROTOCOL(delta[X_AXIS]+add_homing[X_AXIS]);
       SERIAL_PROTOCOLPGM("   Psi+Theta (90):");
-      SERIAL_PROTOCOL(delta[Y_AXIS]-delta[X_AXIS]-90+add_homing[1]);
+      SERIAL_PROTOCOL(delta[Y_AXIS]-delta[X_AXIS]-90+add_homing[Y_AXIS]);
       SERIAL_PROTOCOLLN("");
       
       SERIAL_PROTOCOLPGM("SCARA step Cal - Theta:");
@@ -2883,11 +2883,11 @@ Sigma_Exit:
 	  #ifdef SCARA
 	   if(code_seen('T'))       // Theta
       {
-        add_homing[0] = code_value() ;
+        add_homing[X_AXIS] = code_value() ;
       }
       if(code_seen('P'))       // Psi
       {
-        add_homing[1] = code_value() ;
+        add_homing[Y_AXIS] = code_value() ;
       }
 	  #endif
       break;
@@ -3275,11 +3275,11 @@ Sigma_Exit:
       //SERIAL_ECHOLN(" Soft endstops disabled ");
       if(Stopped == false) {
         //get_coordinates(); // For X Y Z E F
-        delta[0] = 0;
-        delta[1] = 120;
+        delta[X_AXIS] = 0;
+        delta[Y_AXIS] = 120;
         calculate_SCARA_forward_Transform(delta);
-        destination[0] = delta[0]/axis_scaling[X_AXIS];
-        destination[1] = delta[1]/axis_scaling[Y_AXIS];
+        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
+        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
         
         prepare_move();
         //ClearToSend();
@@ -3293,11 +3293,11 @@ Sigma_Exit:
       //SERIAL_ECHOLN(" Soft endstops disabled ");
       if(Stopped == false) {
         //get_coordinates(); // For X Y Z E F
-        delta[0] = 90;
-        delta[1] = 130;
+        delta[X_AXIS] = 90;
+        delta[Y_AXIS] = 130;
         calculate_SCARA_forward_Transform(delta);
-        destination[0] = delta[0]/axis_scaling[X_AXIS];
-        destination[1] = delta[1]/axis_scaling[Y_AXIS];
+        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
+        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
         
         prepare_move();
         //ClearToSend();
@@ -3310,11 +3310,11 @@ Sigma_Exit:
       //SERIAL_ECHOLN(" Soft endstops disabled ");
       if(Stopped == false) {
         //get_coordinates(); // For X Y Z E F
-        delta[0] = 60;
-        delta[1] = 180;
+        delta[X_AXIS] = 60;
+        delta[Y_AXIS] = 180;
         calculate_SCARA_forward_Transform(delta);
-        destination[0] = delta[0]/axis_scaling[X_AXIS];
-        destination[1] = delta[1]/axis_scaling[Y_AXIS];
+        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
+        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
         
         prepare_move();
         //ClearToSend();
@@ -3327,11 +3327,11 @@ Sigma_Exit:
       //SERIAL_ECHOLN(" Soft endstops disabled ");
       if(Stopped == false) {
         //get_coordinates(); // For X Y Z E F
-        delta[0] = 50;
-        delta[1] = 90;
+        delta[X_AXIS] = 50;
+        delta[Y_AXIS] = 90;
         calculate_SCARA_forward_Transform(delta);
-        destination[0] = delta[0]/axis_scaling[X_AXIS];
-        destination[1] = delta[1]/axis_scaling[Y_AXIS];
+        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
+        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS];
         
         prepare_move();
         //ClearToSend();
@@ -3344,11 +3344,11 @@ Sigma_Exit:
       //SERIAL_ECHOLN(" Soft endstops disabled ");
       if(Stopped == false) {
         //get_coordinates(); // For X Y Z E F
-        delta[0] = 45;
-        delta[1] = 135;
+        delta[X_AXIS] = 45;
+        delta[Y_AXIS] = 135;
         calculate_SCARA_forward_Transform(delta);
-        destination[0] = delta[0]/axis_scaling[X_AXIS];
-        destination[1] = delta[1]/axis_scaling[Y_AXIS]; 
+        destination[X_AXIS] = delta[X_AXIS]/axis_scaling[X_AXIS];
+        destination[Y_AXIS] = delta[Y_AXIS]/axis_scaling[Y_AXIS]; 
         
         prepare_move();
         //ClearToSend();
@@ -4020,9 +4020,9 @@ for (int s = 1; s <= steps; s++) {
 
 	
 	calculate_delta(destination);
-         //SERIAL_ECHOPGM("destination[0]="); SERIAL_ECHOLN(destination[0]);
-         //SERIAL_ECHOPGM("destination[1]="); SERIAL_ECHOLN(destination[1]);
-         //SERIAL_ECHOPGM("destination[2]="); SERIAL_ECHOLN(destination[2]);
+         //SERIAL_ECHOPGM("destination[X_AXIS]="); SERIAL_ECHOLN(destination[X_AXIS]);
+         //SERIAL_ECHOPGM("destination[Y_AXIS]="); SERIAL_ECHOLN(destination[Y_AXIS]);
+         //SERIAL_ECHOPGM("destination[Z_AXIS]="); SERIAL_ECHOLN(destination[Z_AXIS]);
          //SERIAL_ECHOPGM("delta[X_AXIS]="); SERIAL_ECHOLN(delta[X_AXIS]);
          //SERIAL_ECHOPGM("delta[Y_AXIS]="); SERIAL_ECHOLN(delta[Y_AXIS]);
          //SERIAL_ECHOPGM("delta[Z_AXIS]="); SERIAL_ECHOLN(delta[Z_AXIS]);
diff --git a/Marlin/example_configurations/SCARA/Configuration_adv.h b/Marlin/example_configurations/SCARA/Configuration_adv.h
index 10fbe9b316..840a1b2881 100644
--- a/Marlin/example_configurations/SCARA/Configuration_adv.h
+++ b/Marlin/example_configurations/SCARA/Configuration_adv.h
@@ -353,8 +353,8 @@
 
   #define D_FILAMENT 1.75
   #define STEPS_MM_E 1000
-  #define EXTRUTION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
-  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUTION_AREA)
+  #define EXTRUSION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
+  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUSION_AREA)
 
 #endif // ADVANCE
 
diff --git a/Marlin/example_configurations/delta/Configuration_adv.h b/Marlin/example_configurations/delta/Configuration_adv.h
index 6c9d56886d..edc6580478 100644
--- a/Marlin/example_configurations/delta/Configuration_adv.h
+++ b/Marlin/example_configurations/delta/Configuration_adv.h
@@ -340,8 +340,8 @@
 
   #define D_FILAMENT 2.85
   #define STEPS_MM_E 836
-  #define EXTRUTION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
-  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUTION_AREA)
+  #define EXTRUSION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
+  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUSION_AREA)
 
 #endif // ADVANCE
 
diff --git a/Marlin/example_configurations/makibox/Configuration_adv.h b/Marlin/example_configurations/makibox/Configuration_adv.h
index 312b2b9647..21dbd46d73 100644
--- a/Marlin/example_configurations/makibox/Configuration_adv.h
+++ b/Marlin/example_configurations/makibox/Configuration_adv.h
@@ -344,8 +344,8 @@
 
   #define D_FILAMENT 2.85
   #define STEPS_MM_E 836
-  #define EXTRUTION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
-  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUTION_AREA)
+  #define EXTRUSION_AREA (0.25 * D_FILAMENT * D_FILAMENT * 3.14159)
+  #define STEPS_PER_CUBIC_MM_E (axis_steps_per_unit[E_AXIS]/ EXTRUSION_AREA)
 
 #endif // ADVANCE
 
diff --git a/Marlin/planner.cpp b/Marlin/planner.cpp
index fe617501f1..c8942251e4 100644
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@@ -63,9 +63,9 @@
 //===========================================================================
 
 unsigned long minsegmenttime;
-float max_feedrate[4]; // set the max speeds
-float axis_steps_per_unit[4];
-unsigned long max_acceleration_units_per_sq_second[4]; // Use M201 to override by software
+float max_feedrate[NUM_AXIS]; // set the max speeds
+float axis_steps_per_unit[NUM_AXIS];
+unsigned long max_acceleration_units_per_sq_second[NUM_AXIS]; // Use M201 to override by software
 float minimumfeedrate;
 float acceleration;         // Normal acceleration mm/s^2  THIS IS THE DEFAULT ACCELERATION for all moves. M204 SXXXX
 float retract_acceleration; //  mm/s^2   filament pull-pack and push-forward  while standing still in the other axis M204 TXXXX
@@ -85,8 +85,8 @@ matrix_3x3 plan_bed_level_matrix = {
 #endif // #ifdef ENABLE_AUTO_BED_LEVELING
 
 // The current position of the tool in absolute steps
-long position[4];   //rescaled from extern when axis_steps_per_unit are changed by gcode
-static float previous_speed[4]; // Speed of previous path line segment
+long position[NUM_AXIS];   //rescaled from extern when axis_steps_per_unit are changed by gcode
+static float previous_speed[NUM_AXIS]; // Speed of previous path line segment
 static float previous_nominal_speed; // Nominal speed of previous path line segment
 
 #ifdef AUTOTEMP
@@ -989,7 +989,7 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
   else {
     long acc_dist = estimate_acceleration_distance(0, block->nominal_rate, block->acceleration_st);
     float advance = (STEPS_PER_CUBIC_MM_E * EXTRUDER_ADVANCE_K) * 
-      (current_speed[E_AXIS] * current_speed[E_AXIS] * EXTRUTION_AREA * EXTRUTION_AREA)*256;
+      (current_speed[E_AXIS] * current_speed[E_AXIS] * EXTRUSION_AREA * EXTRUSION_AREA)*256;
     block->advance = advance;
     if(acc_dist == 0) {
       block->advance_rate = 0;
diff --git a/Marlin/planner.h b/Marlin/planner.h
index 837199eb7a..0952b9dd34 100644
--- a/Marlin/planner.h
+++ b/Marlin/planner.h
@@ -106,9 +106,9 @@ void check_axes_activity();
 uint8_t movesplanned(); //return the nr of buffered moves
 
 extern unsigned long minsegmenttime;
-extern float max_feedrate[4]; // set the max speeds
-extern float axis_steps_per_unit[4];
-extern unsigned long max_acceleration_units_per_sq_second[4]; // Use M201 to override by software
+extern float max_feedrate[NUM_AXIS]; // set the max speeds
+extern float axis_steps_per_unit[NUM_AXIS];
+extern unsigned long max_acceleration_units_per_sq_second[NUM_AXIS]; // Use M201 to override by software
 extern float minimumfeedrate;
 extern float acceleration;         // Normal acceleration mm/s^2  THIS IS THE DEFAULT ACCELERATION for all moves. M204 SXXXX
 extern float retract_acceleration; //  mm/s^2   filament pull-pack and push-forward  while standing still in the other axis M204 TXXXX
@@ -152,14 +152,7 @@ FORCE_INLINE block_t *plan_get_current_block()
 }
 
 // Returns true if the buffer has a queued block, false otherwise
-FORCE_INLINE bool blocks_queued() 
-{
-  if (block_buffer_head == block_buffer_tail) { 
-    return false; 
-  }
-  else
-    return true;
-}
+FORCE_INLINE bool blocks_queued() { return (block_buffer_head != block_buffer_tail); }
 
 #ifdef PREVENT_DANGEROUS_EXTRUDE
 void set_extrude_min_temp(float temp);