The primary weakness of these little two-strokes is the fuel pump, which is inside the carburetor. It's actually nothing more than a paper-thin rubber membrane, very delicate and flexible.
Regular pump gas contains up to 10% ethanol everywhere in the US. Ethanol is bad news for delicate rubber and plastic parts. Even worse, ethanol is hydrophilic, which is a fancy way of saying that it gets along with water quite well. These carbs fail because (1) the fuel pump membrane becomes too stiff to function or (2) the water that ethanol drags along with it plugs the tiny passages in the carb or leaves calcium deposits. Either way, your weed-whacker won't start in the spring.
I run pump gas in my two-strokes during the spring and summer, when I know I'll be using them often. Around the first of September, I switch to the canned stuff. By the time cold weather hits, everything is ready for the long winter nap, and in the spring will be ready to go.