Oxygen is the big enemy of gasoline. It is the oxidation products
that gum up the carburator and engine. Heat accelerates. Stabilizers
like Sta-bil deter this. So my advice is to store the tank nearly full
to displace air, with stabilizer under cool conditions. With
lawnmower, snow thrower, generator, chain saw and weed wacker, it is a
PITA to run engines dry at the end of every season so I just store
with gas containing Sta-bil.

It is also a good idea to get your equipment running weeks before you
will need it. Otherwise, repair shops are full of equipment that
failed to start and you will have a long wait to get yours repaired.