All good, I sometimes overreact & take things personal when I shouldn’t. I can promise you I have never scraped carbon off an exhaust port, I would pull the screens sometimes on the muffler and throw them in a little gas but I kept air filters clean, every Sunday I would blow saw off-out, grease needle bearing, I would grind chain every night(sqaure) & run the piss out of these ported saws. I just don’t see anything special about cutting 10 acres with one saw, this is not uncommon with a correctly tuned, maintained pro saw. Stihl 660 or a 390 husky in my case. One that wasn’t jerked on when pinched causing air leaks etc. I’m sure there are better oils than Stihl ultra but it is not horrible oil as some have said. I believe running a really sharp chain & good common sense when falling and bucking is the key to longevity. I could be wrong & just lucky with my saws in the past.