Chainsaws are a lot like cars.....a lot of how long they run depends on how well we take care of them.
No disrespect intended or implied, but I,be treated my Stihl saws like crap for the last 20 years and they all still run great. I keep bar oil in them and always use Stihl 2 cycle oil to mix my fuel. I only clean the bar if I take the chain off for some reason which is rare. I file the chains about every other tank of fuel. I only cut about 6 cord a year, mostly hickory. The air filter area should be blown out after every use, but mine only gets cleaned a few times per year. Point is that saws are pretty durable so long as you don't ever use straight gas in them. Straight gasing is the most common cause of death for any good saw.