No ammo company would sell ammo that required limiting its use in a S&W to 5 rounds a few times a year. I'm sorry, that is simply a ridiculous notion.
I guess I'll have to put this on my tombstone.
+P is NOT loaded to high pressures.
It is loaded 3,000 PSI BELOW maximum allowable.
The myth of +P being a powerful load is just that, a myth not based in any form of reality.
I recommend that you shoot as much +P as you care to buy. In my opinion +P is nothing more than a fairly weak gallery load. It's a 125 at 925. C'mon, that's weak sister ammo! Much too wimpy for me to trust to save my life.