I've used the Brookie Knee highs and water shoe combo for about 5 years, and have put in some 10-12 days solo, and have never had a foot problem.
JJS is right about changing into camp shoes. The first thing I do in camp is string my dry-fly, then put some coffee water on, and last but very important, I change into dry wool socks and camp shoes.
I dry my feet before I put on dry wool socks, and use a little medicated foot powder ( Gold Bond travel size). Every night I turn my fleece booties inside out, and dry out the liner sock, or replace with clean dry one next morning.
On camp days, if its sunny, I'll turn the Knee highs inside out and lay out in the sun and that keeps any mildew from forming.
First thing they teach you in the Army is to take care of your feet, its been good advice for many years and still holds true, especially in wet conditions ;)