As Trader said, the engines vary. After a month, the brush cutter I bought about 1983 will be hard to start. Then I'll find that the mixture is either too lean or too rich. I may have to take the carburetor apart and use a q-tip to remove gunk from a screen. For some reason, when I get it running, a tiny bit of Sea Foam in the tank will clear up problems. I haven't figured out what's in Sea Foam that will clean a carburetor.
For decades, I've been mixing my 2-cycle fuel in a pint- or quart-sized soda bottle. It was sitting around too long if I mixed a gallon. In a soda bottle, I can see that the oil is fully mixed. If the bottom is clear, I can see any water-ethanol. Best of all, it's sealed, so it can't pick up moisture.
The fuel tank on the brush cutter is another matter. I find it best to leave it nearly empty. If fuel can absorb a certain amount of water per gallon, less fuel will absorb less water.