Based on a phase I went through involving getting rid of almost all my possessions, you can get rid of ~50% of your stuff and barely notice. But that last 10-20% is so amazingly critical, you come to appreciate it and the work that must have gone into it more. That said, having things that are useful and last never gets old, just make donating something you do as often as shopping. Also that is a pretty strange but interesting hobby.
I've had a thing ever since grad school (I lived in a 400 sq. ft. apartment, so it was necessity then) that if I buy a thing, I have to donate something else -- particularly for clothes. It's amazing how much less crap I've accumulated than friends and family of a similar age.
