Stabilizers are marketing BS, they can’t rejuvenate old fuel and they generally work by introducing an additional component that reduces the ability of the fuel (mostly the methanol content) to absorb water … however they rarely have a positive effect over all because they cause other problems.

Long shelf-life fuel is made in the refining stage. European standard E10 petrol can last a year or more if it’s stored correctly … I know this because I sometimes do store it for that long by accident.