Usually, your softener has a little timer brain that handles this at 2 AM, which is nice. But sometimes that little brain gets confused. Maybe you came home from vacation and ran a marathon of laundry and dishwashing. Maybe you had a party and used a billion gallons of water. The softener is exhausted. You’ll know because your water suddenly tastes like you licked a rock.
Another classic reason: you forgot to buy salt for a month, and now the system is just sitting there, depressed. Manual regeneration wakes it up and tells it to get back to work with a fresh tank of salt.
