I just bought some spearmint and rosemary 50ml e/os from a different supplier and on the bottle it says they should be used within 6 months of opening. Is this true for all e/os?
naw, just store properly and most are good for years (refrigerated, in amber glass bottles). even at room temp you are good if the temperature doesn't fluctuate much and isn't too hot.
citrus seem to be more sensitive than others, but even those can last if properly stored.
well not really - it's probably just that the are making recommendations based on the lowest common denominator = assuming the most sensitive oils and that people won't store properly.