Somehow I always manage to jam pack my wallet with more stuff than it was intended to hold. Regularly cleaning out the contents and re-organizing helps me in a couple of ways. Instead of just throwing out everything that looks like it doesn't belong, I look at every folded receipt to see what purchases I've recently made. More lunch receipts than usual means I need to bring my lunch more the following week. When I come across receipts for items I've been meaning to return, I stick the item in my bag or set it out on the table to remind me it needs to go in the mail. Added bonus: you won't have things spilling out of your wallet when your hands are full and you're trying to pay for your morning coffee!