They need to be depended on at a moments notice, AND sit idle for weeks at a time. The pre-mix cans are crazy expensive, but so are carbide chainsaw chains, and both of these are really suited for these specialized uses. In these uses, they're well worth every penny. Even Stihl doesn't recommend that lawn care professionals run their machines on their moto-mix all the time. They just say to empty the tank and use a shot of it to keep it over the winter.