How long will these mowers last? Pretty much depends upon how well you take care of it. Having a more costly, better made mower should mean it lasts longer, but those need good maintenance too. Keep in mind that heavier-duty transmissions and higher power motors are needed for heavier chassis mowers with bigger cutting decks. The heavier the machine, the bigger components needed. A unit that is smaller and lighter with "lower end" components doesn't necessarily mean it isn't quality, just the correct spec for the size, weight, and performance of the machine. A ZT-3400 transaxle is considered commercial grade. However, there is a world of difference between a ZT-3400 and a ZT-4400. 4-lug vs 5-lug hubs is one indicator. But of course, the 4400 is designed for higher horsepower engines and heavy chassis mowers.