I'll +1 everything that was said here. Good advice.
In addition to it, if you wish to minimize the dirt weakening fabric issue, just rinse your combats after a game with cool water. No detergent. Rub the dirt out either by rubbing the fabric against itself or using your hands,continue until the runoff is fairly clear.
Yesterday's tears are today's wounds
Today's wounds are tomorrows scars
Tomorrows scars are your life's war cry...
-Fuck 'em up Gentlemen