I'm with the smelly crew here I can't imagine washing clothes every day... after a day's riding it's sometimes almost too much of an effort to roll my sleeping bag out and crawl into it!

I ride in t-shirts with cut off arms made of... wait for it.... COTTON!!!! (ah BF blasphemy!!!), which don't get as smelly as all this modern nonsense

I usually wash clothes once a week on a rest day at a campsite laundry (on my recent tour in the US I was pleasantly surprised as to how cheap this was, $1 or $1.25 wash, and the same for the dryer... As someone else mentioned ALL my clothes get washed (got a couple of funny looks wearing my rain gear (and nothing else) when it was really hot...)

In california I bought a bear vault which was great for carrying food, sitting on when the ground was wet, or washing riding gear in when no other option was available... The only "con" to the bear vault was it's weight.