I mainly shot competition, both Bullseye and IDPA, and mostly Bullseye. You won't win any competitions if your gun keeps jamming. Reliability is very important, but not a matter of life and death. Also I'm not worried about things like lint or dirt getting in my guns and I never start a competition with a gun that hasn't been fully cleaned lubed and ready to go.
Now for most competition (except Distinguished Pistol) I'm shooting reduced loads. In my 45 wad gun with a red dot scope mounted on the slide, I use a 12# spring. On the 45 I use for IDPA, I use a 16 lb spring for 230 grain cast bullets with a reduced load (~3.6 grains Bullseye), and as mentioned before, I use a 22# spring in my Service Pistol for Hard Ball loads. In each case, the choice of spring was determined by putting in progressively stronger springs until the gun didn't work reliably, then drop back.
I wouldn't use the same procedure for a self defense gun. Varying conditions, lint, and the need for a bigger margin of error make it necessary that your not operating anywhere near the edge of reliability. Of course I don't put 20,000 rounds per year through my self defense guns like I do with my Bullseye guns.