It really costs me nothing because I have done my own work for many years now. The only part that I actually replace is the Rebound Spring. I bought 13 pounders in bulk many years ago and they were under a buck or so each. You can get lighter RB Springs but I dislike tardy trigger returns. There are a few Revolvers that I have gone with lighter RB springs but they get shot 99% single action mode and only at Range.
I do remove burrs, smooth out rough pieces, slightly shorten strain screws, polish certain parts, but never replace Main Springs and NEVER stone the Hammer/Sear engagement surfaces. I also always lean on the side of reliability and don't try to get actions too light. I am more interested in SMOOTH & RELIABLE rather than light and maybe! I do have a few Target ONLY guns that are a bit on the light side but they NEVER see a holster and are ONLY used at the Range for paper punching and competition. I've never had any FTF, but even if I did, I only risk messing up a target or at worst loosing match - not my life.
I have also slicked up a few 1911's but more specialized tooling is required (but readily available from Brownell's). Again - err on the side of caution and safety and SMOOTHNESS, CRISP and CREEPLESS actions are what I strive for.
NOTE:
Any gun I own that has been altered or modified always has a note in the box stating exactly what was done along with the original parts so it can be restored to Factory specs. I never modify original parts and have bought plenty of extra RB Springs and Strain Screws. I also have my share of Hammers, Triggers and Grips that I sometimes will swap out - but the un-altered originals are always in the box.