One time I found the perfect pair of sneakers, so I went back to the store a few weeks later and bought a second pair as backup.  Last summer I found the best sandals I've ever worn, so I bought a backup pair of them as well.  I do this with jeans and shirts and a few other things because I have peculiar and picky tastes and am often disappointed by the newer version of something I already own.  I'm obviously not in the running for any fashion awards, but at least I can satisfy my silly little need for regularity.