I think you have too much gun when it is not enjoyable for you to shoot it.
I'm still pretty young comparatively, but previous jobs (and perhaps genetics) have caused me to have bad wrists. So, if I shoot larger bore handguns it's not fun for me because in the back of my mind I'm questioning if I will be hurting the next day.
I really don't see myself going over 9mm in any handgun anytime soon. I am a bigger guy, maybe I just don have the technique down like some have said. But the thing is, I don't want to invest in a larger caliber to only find out that even with good technique it still makes my wrists sore.