Living with a hoarder is also good for this. Heh. Though since I can only control myself, it's not actually helpful at getting stuff out of my house. :P But, hooray! I'm glad you are having this opportunity to evaluate the necessities. Most stuff doesn't bring real happiness.
My wife isn't a hoarder but we definitely have differing approaches to "stuff." I could move tomorrow and fit everything I care about into a hatchback, and I love plain empty rooms with lots of smooth surfaces. She has an entire two-story barn full antiques and stuff she's accumulated, and decorates with lots of pictures, sculptures and "decorative accents" (knick-knacks). So there's always a significant push-pull going on when it's time for a trip to the dump.
I'd be interested to hear how you handle things with your partner.
Hmm, well, my husband I don't know that I handle it wonderfully. I mostly ignore it to the best of my ability, and then put my foot down when his stuff starts to creep into shared living spaces. I do think he's made a break through in the last few years in that he admits he has a problem, which is the first step, and that he wants to solve it, which is the second. I remain hopeful that he will defeat his problem over time, but I'm not sure. Frankly, he is resistant to what I think are the fastest and easiest fixes, determined to do it all himself, and, I think, that just makes it harder for him to part with things. We'll see. He's got a plan for how he wants to tackle it, but whether it will come to fruition, only time will tell. I adore him, though, so...he's got me no matter what.