I exercise nearly every day - sometimes twice. In the course of a week I can get through probably 8 sets of exercise clothes. I like to make sure if I'm doing a workout I work up a nice sweat but this does mean that my clothes don't last long. Despite always washing them the same day they often still come out smelling and I currently need to replace nearly all of my stuff.
Where do you get yours? I replace fairly often so look for cheapest breathable stuff possible. I've tried buying more expensive stuff hoping it will last longer but it just doesn't.