the answer to this oft asked question is the same as the answer to a lot of mysteries.
"Do the numbers!"
simply stated, if you can afford enough high pressure ammo to wear out your P-6 or anyother Sig/Beretta/Glock/Smith/whatever, you can easily afford to buy a couple of new guns.
+P or +P+ ammo will accelerate the wear on your gun and shorten its life. There is no doubt that any sig can go 100,000 rounds before giving up the ghost. If +Ps cut that life in half, do the numbers, how much money would you have to spend on that many high pressure premium loads? My calculator says between $10,000 and $25,000 depending how hard a bargan you drive.
If you can afford that much, you can easily buy a new gun or two.