The exact duration will depend on several factors, including the quality of the fuel, and the engine’s operating conditions. But generally, the Verstärker octane booster last in the fuel tank for over a year. It doesn’t mean a pour of one bottle is enough for 1 year of using the car, it last for 1 year in the fuel tank if the car doesn’t refuel. We strongly recommend pouring 1 bottle of the Verstärker octane booster on every fuel fill-up.