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e-liquids will last longer if refrigerated or frozen
most e-liquids will have a shelf life of 1 year+ before the nic starts breaking down
most major steeping taste change is complete within the 1st 30 days - most changes after that are normally not noticeable
steeping will blend the and smooth the flavors, so it normally gets better (unless it is a flavor that you thought you might like but is nasty no matter what - taste is subjective to each person, same as food and beverage choices (I could never drink anything diet, yuck, pooey)