My late husband had that problem. My fiance has that problem. They both had humble (not poor) lifestyles in their childhoods, but then so did I!! After having to clean out the garage, attic, closets, etc., by myself after my late husband's death, I decided not to let that happen again. So, with my fiance, I laid down the rules about stuffed attics, garages, closets, unpacked boxes full of junk from previous move. I told him it really unnerves me to live like that or even see it. We have three garages, no basement, an attic. Told him he can have two garages but if the one next to mine is messy, he has to build a wall. I have to approve everything that goes in the attic or closets. I remind him constantly: You wanted a workshop so don't fill up your work table with junk. Do you really want a big, broken garage door opener to "work on some day" or do you want to be able to find what you need? Or: is it agreed that if you don't use that in 2 years, then it goes? If you both watch that cable show about all the couples (male and female) that struggle with this same problem, you'd laugh. Some are so bad that one of the two can't sleep on the bed because it has piles on it. Or, the teen's won't have friends over to visit out of embarrassment. I think hey have to have a goal to replace their fear of "But I might use that one day." A yard sale with a goal of having a room redone or a specific vacation trip might motivate him. On this show: First, they agree to change. Then they cry. Then they get mad. Then the team pushes them ever forward, have the garage sale, redo their room, then everyone's happy. Repeats itself every time. Good luck. There are books on this too. Once they let go of a few things and realize they don't miss them, I think it isn't as hard as they thought it would be.