In STO, Benzites are playable characters and it's the player's choice whether to install a breather or not. I'm trying to think of a real life analog but nothings springs to mind.
Kids with asthma. Some have to carry their puffer everywhere they go. Others just on sports afternoon. Others need to be placed on a nebulizer every night.
Diabetics. Some always carry jelly beans or chocolate. Others inject insulin every day, but not all.