I'm the exact opposite. I can't get something new unless I sell the first one. I'm notorious for getting a saddle, using it a couple times, and then selling it for one I might like better. So far this summer I have sold 1 saddle, traded another saddle, and I'm getting ready to sell the one I got in the trade so I can buy a different saddle. If It doesn't fit my horse, I can't use it.
I have one saddle that I will never sell though, it's a back up saddle. I do the same with bridles. Only reason I would sell a bridle is if I found one I liked better though. I use the money I got from the sale to buy a different one. I can only use one at a time!
Polo wraps are a whole different story. I love polo wraps. I can never sell them. I once gave a gigantic bag of polo wraps to a friend a couple years ago because I simply had too many. Wishing I kept a couple of them though because I have to buy duplicates since I liked the design so much!