CowboyPete said:It depends largely on the training regimen, not the martial art. There are Kyokushin Karate dojos where they do nothing for hands. Kung Fu is taught in my mall (yeah, it's gross) and you can imagine the type of training they have there...
I would say most TMA's are better about this than things like boxing, Thai boxing, what have you because they use gloves. Again, though, it's dependent on the place you're learning and what you do on your own free time.
Think through the long-term effects of conditoning your limbs...Mas Oyama being a notable example. If you are for it, TMAs are probably better for it though I am not convinced about the merits of doing so