Use -= for odd case
Extract increase_quality
Swap independent conditions
Extract decrease_quality
Un-nest conditional
Use increase_quality one more time
Move sell_in adjustment to top
Extract age
Extract update_quality
Use positive logic for top conditional
Use positive logic for second conditional
Use positive logic for last conditional
Use if..elsif
Extract Sulfuras to a guard clause
Convert to guard clause in age
Move Sulfuras guard clause up to update
Split first conditional
Unify normal item conditions
Unify backstage pass conditions
Unify aged brie conditions