I have 2 kids in college and I'm trying to sell my house. So I've decluttered to make the house presentable and I'm waiting for my kids to graduate and get their own places so I can give them their crap back. Storage unit makes sense for me. But this is likely to last only 2-4 years and then I'll have downsized enough.
My parents gave me my “crap” back and it went straight into the trash. When my kids moved out, their “crap” went to Goodwill or the trash.
Are you sure they even will want it back? Might be better to just donate it all now and save the money.