I have 4 pairs but only wear two (mostly only one, really).

One pair of red Sidis that I wear for my road riding, which is most of the riding I do.

One pair of Shimano mtn bike shoes that I wear on the rare occasions that I use my mountain bike.

One pair of silver Sidis that are too small - they seemed okay when I bought them but are uncomfortable as my feet swell during long rides on hot days. I really don't know why I keep them, I just don't know what else to do with them and they were too expensive to just throw out.

One pair of Nike mountain bike shoes that were a free gift for my participation in the Wildflower Mountain Biking for Women video -- Nike was a a sponsor of the video. They're my backup shoes for mtn biking, but since I don't do much of that these days, I haven't needed them in a while.

I will keep the current Sidis until they wear out.