I have two generators; 5500 watt and 2800 watt. They are used for work stuff most often running tools, lights, and equipment. I just had the 5500 watt gone over by a tech. First time since I got it about 10 years ago and I spent about $300 on that effort. Worth it considering the replacement cost. (At the time, it would not start. Not much good if it won't start or run.)
It would not start and I removed the spark plug thinking to replace it. Called the tech to see what is the correct plug and then bought it at an auto parts store. The problem was when I went to screw it in, it was not "finger turning" as is normal at least to start and I was afraid to cross thread things in the softer aluminum housing. The correct angle was not apparent looking at it. So, that ended that and a trip to the tech was in order. The tech basically said it was full on junk in part because of letting the fuel sit in it for long periods of time. So, he cleaned and replaced whatever stuff needed to be replaced.
Both have Honda engines and been extremely reliable overall until the one time with the 5500 which resulted in its repair. The generator tech suggested only non-ethanol fuels to be used unless you are just going to burn it up quickly. The 5500 is powerful enough for what I have in mind; selective running of portions of the house circuits and all non-220 stuff which the HVAC and stove are. So good enough for week long kind of power outages.
So far, I have only needed a generator once at home when the power went out following a close miss by a tornado. I was expecting a several day outage and immediately headed to the gas station to supplement my fuel supply to about 25 gallons of gas. Got home and the power was on. Oh well....