I put fuel stabalizer in my runner before i flew back to korea, i won't be back till another 4.5 months, and my dad starts it weekly and drives maybe a mile at that time. so maybe 20 miles will be driven when i get back, that's why i added it. i believe fuel goes bad within 60 days or something like that. so if you fill it up and can't use all the gas within that time, i probably would, so it doesn't go bad.