How long does it take for fuel to go bad?

Fuel can begin to degrade within a few months, with gasoline typically losing its effectiveness after about three to six months due to evaporation and oxidation. Diesel fuel can last longer, around six to twelve months, but can still develop issues like microbial growth. Factors such as storage conditions, exposure to air, and the presence of moisture can accelerate the deterioration process. Proper storage in a cool, dry place and using fuel stabilizers can help extend its shelf life.