Proper storage is the single most important factor in preserving your essential oils’ quality and potency. The three main enemies of essential oils are heat, light, and oxygen. Always store oils in dark amber or cobalt glass bottles — never clear glass or plastic. Keep them in a cool, dry location away from direct sunlight; a drawer, cabinet, or dedicated storage box works well. Always tighten caps firmly after each use to minimise oxygen exposure. For citrus oils, which have the shortest shelf life of 1–2 years, storing them in the refrigerator significantly extends their freshness. Label each bottle with the purchase date so you can track freshness, and if a bottle is only partially used, consider transferring it to a smaller container to reduce air space.