I play without fatigue because my PC can't handle what is, IMHO, the only good fatigue model for SH3:
RUB 1xTC! For anyone who doesn't know: RUB 1xTC is a misnomer because it actually works at any TC up to and including your 3D TC setting (default 32). By increasing 3D TC to match your maximum TC you can have the RUB 1xTC "battle fatigue" model working all the time... the only problem is that SH3 will render everything all the time, even when you're looking at your map at max TC. This puts quite a strain on your system at higher TC settings. Modern machines should be able to handle it without breaking a sweat, but my 3YO rig tends to crumple under the pressure when a convoy is around.