My #cho 2601 is 15 years old, the first 7 years it was used commercially. Minimum 20 hours a week 30 weeks a year. For the last 8 years it is used 15 minutes a week 30 weeks a year. Still starts pretty easy and literally had to adjust the carb for the first time last year. Had to clean out the carbon from the exhaust port once. Change the air filter once every couple of years now, back when it was used hard maybe twice a year. Thats it. It still runs but you can tell she is tired. It is usually used at around 50-70% throttle. My Stihl BR400 blower is just as old and has seen similar usage and still starts and runs good. No idea why yours are living such a short life. Check the plugs, the fuel filter, carb, exhaust port. Keep them all maintained and they should run for a decade imho.