We do not use synthetic preservatives or fillers, so our essential oils have expired time. But, most of our essential oils are very stable and lasting for years - even decades - without experiencing deterioration in quality or aroma or chemical composition. Each essential oil has different durability. Tea Tree and Lemon, for example, are more susceptible to oxidation than other essential oils. The packaging of Young Living Essential Oil is amber glass bottles. The aim is to protect them from sunlight, but you can help extend their life by putting them away from heat and sunlight.