This is what I suspect for a normal, average cracker like myself. I don't do it every 5 minutes like some but maybe 5 or 6 times a day. I am 31 now and have been doing it for at least 20 years now and don't notice any issues with my hands. Maybe in another 20 I will regret it. Then again I think I will regret many other things more in 20 years time ;)