I just pulled the paperwork on my dad's Homeite XL-12. It was purchased new in 1964. He ran it for property cleanup, until 1980, when he had a woodburner installed. Cut 7-10 cord of firewood a year until 1992; no problems. He probably ran it lean sometime in there. In 92, he had the cylinder honed, and all gaskets replaced, carb rebuilt, etc. In 96, I started using it. Last year, I retired it because of the starter pulley. I pulled it out of retirement this year, just to check on it. That cylinder looks good. I replaced the starter assembly with one from a parts saw, replaced the fuel line, and that thing runs like a champ.
So, I have a 32 year old saw. If my math is right, it has cut 175-250 cord of firewood plus all the property cleanup. For a firewood saw, it seems to have held up well, and looks like it will keep going for a long time yet. I just wish I had the air compressor he used to use at work to keep that thing clean. Any decent saw (not even a "pro" model) will last a long time, if you take care of it. Hang around here long enough, and that won't be a problem.