This is a very subjective question. I say, it all depends on the workout. If you work on your abs using weights, then you should not work them everyday as it is just like any other muscle group. However, if you just do the basic ab workouts (without weights), which I've done in the past, that should not hurt at all since most of our daily activities involve the ab muscles.
-------------- **_Robert_**
Pain is temporary; glory is forever!