Carry salt to it, several times a year. The practical question nobody asks before installation: who is carrying it, from where, and over what? A bag of softener salt is heavy. A location down a narrow stair, behind stored items, or across a garage in winter turns a routine task into one that gets postponed — and postponed salt means hard water returning without anyone deciding it should. Make it easy: site the unit somewhere with a straightforward route from where you'd park or unload. It's a legitimate design criterion, and it's cheaper to consider now than to relocate later.