Yes, you're not instantly going to develop athletes foot if you don't wash your socks every day. And take it from a girl who has been wearing her cycling shorts more than one day in a row without washing them in between for almost 20 years now ... you're not going to develop saddle sores because you don't wash your shorts after every single wear. The only saddle sore I've ever had was a friction sore caused by wearing loose shorts on a rainy 600K while using a gel saddle.
The whole washing your clothes after every use thing is an "old wives tale" perpetuated by our mothers who didn't want us to go out and possibly get in an accident and end up in the hospital with dirty underwear.
Yes, it is important to keep your body clean. It's a very good idea to stop mid-ride and give yourself a wash in a convenience store washroom or whatever ... or if you don't have water available, baby wipes work. Doing this washes away sweat and particularly the salt in sweat. And it's a good idea to give yourself a wash at the end of the day. But as for your shorts, if you hang them up to dry out overnight, they should be good for at least one more day ... maybe 3 or 4 or 5 days.
