Preventing Discoloration of Men's Dress Pants?

If you must fold them use plastic hangers. But the best way is to hang them straight by the cuffs using a clip hanger.

I found that pants discolor more from washing than from the way they are hung. Try washing the pants inside out. Also, I found that Dockers pants discolor relatively quickly. The newest Haggar pants are unbelievable. They never fade!