Most people over the age of like 65 tend to be at least light hoarders because they're boomers and grew up with 9 siblings in a 4 bedroom house and never got new clothes they were all hand me downs and for christmas they got eat an orange and on their birthday they would share an apple etc.
so they learned to never throw anything out because everything has a use, so it would seem.
My parents were and still are light hoarders where it's not like pic related where they have stacks of books on stairs and there's shoes on the dining table and piss and shit everywhere
but it's still enough where the garage door doesn't open all the way through because there's stuff in the back of it and it's impossible to reach certain things because of all the stuff. The freezers are all filled at 99.9999% capacity. There's enough tools in the fuckin basement to rebuild all of africa. Quite a few old TVs and stereo equipment that aren't broken but are just collecting dust.
But if they're not boomers, it's usually a form of OCD or trauma or something.
There's also different forms, there are those that collect stuff, real things that would have a use or value but there's just too much of it. Lots of compulsive shoppers.
Then there's those that shit in coffee cans and piss in soda bottles, they tend to be more depressive or agoraphobic or something.