I am still surprised at how much stuff I have after the loads and loads of stuff I've gotten rid of in the last 2 years! Most of it I shed on moving... and then the last few months I've rid myself of more! But, I've still got a fully equipped house.
My biggest problem is that I have way too many hobbies. I've got large amounts of things stored for a variety of different hobbies from sewing and crafts, cooking and camping gear in the house to kayaking and motorcycling in the garage, gardening takes up my work shed and part of the garage.... and then there are all the books.....
To really get rid of a lot of hard to store stuff - I'd have to give up a hobby! Not happening!