Me too.
At the end of summer I've always put whatever small-engine gas was left over, into the car. Even if it included 2 cycle oil. Likewise the remainder of a can of Coleman fuel after the last camping trip of the year. I think this is preferable to storing it over the winter. It's never caused a problem. Better to consume it than to let it evaporate and add to the hole in the ozone layer.
Decomposed gas has a bad smell and I would draw the line at that. If it smells bad then it should only go in small proportions to a carbureted engine, since it could foul injectors.
Gasoline is a powerful solvent. I think as long as the good fuel is at least 20:1 to the old stuff, then no problem.
On the other hand I considered the advice I received here and didn't try to burn years-old kerosene in my diesel tractor due to the risk of damaging the injectors.