My significant other and I bought a house almost exactly a year ago and we've accumulated a 'house full' but I don't feel like we're at all cluttered in about 90% of our home.
Haha! This sounds JUST like me. My office is the 10% that is just a little crazy at times. (Thank goodness for doors that can close sometimes.) I never know what props I might need so I have a wide range of just stuff that I don't NEED but might need some day. (Like fairy wings and birthday hats... I mean, who knows, right?) Art supplies I find on sale, color swatches, different paper types and weights, etc. I specifically love objects that are unique in color, reflection, shape, and texture. I mean, I needed alligator felt in this last week. You never know what you'll need!
As far as personal items: the only thing I have too much of is novelty t-shirts and perfume/lotion/soap/etc. that I've gotten in gift baskets. I can justify keeping the shirts because I do wear them a lot while painting, hiking, or going to the gym. The girly smelly stuff? -_- I almost resent it all. People keep buying it for me because they see me use it but I'm only using it because I have too much of it and don't want to throw it away or it to go to waste. After this Xmas I'm going to just go through and donate everything I haven't opened and maybe get to go buy whatever smell I want to smell like this year! (Yes, I've asked them to stop but someone I just met or a family member always does this! I'd rather have a gift card to Bath and Body instead of you deciding I should smell like River Rowboat Mystic Journey this month.... at least ask me what I like.)
PS: I'm so proud of my house. It is so difficult not spamming this post with pictures of the place.