I'm wrestling with this right now. Some of the stuff I'm trying to sell isn't moving, despite being in perfectly good condition. It seems people would just rather buy new.
On the other hand, I recently bought a carpet shampoo machine because I was tired of lugging home the rentals, finding they weren't completely clean from the last renter, and then having to race to shampoo every rug and carpet in time to get the machine back on time. It was worth it to me to be able to clean when I wanted to and even just do one carpet at a time if need be. And of course, it gets done more often. So, for that reason - and the fact that it was on sale for half price - it was worth buying.
My husband is a bit of a packrat, it's about the only thing we ever have arguments about. I used to be, but my shopping habits were drastically changed when I volunteered for an annual charity rummage sale three or four years in a row. The first year I put on my change apron, walked out into the sale, and looked at tables and tables piled high with donations. The thought that ran through my mind was "Wow, this is how we live in North America. We have so much stuff that we have to give it away to keep from drowning in it." It changed the way I shop. I look at non-essential items and ask myself if I'll use it often enough to justify buying it. Things like seasonal ornaments, I buy at thrift shops and then re-donate. When I see knick-knacks in places like Winners (T.J. Maxx in the 'States) I wonder how long it will be before I see it in a yard sale or thrift store.