There are a couple of ways to answer how long do perfumes last – by how long it lasts when you have your perfume on; and shelf life.
When you have your perfume on
Quite simply, it’ll last anywhere from 4 to 12 hours depending on whether it’s Eau de Toilette, Eau de Parfum or perfume.
Shelf life of perfumes
Once a fragrance is opened, it has a shelf life of around a year. Thereupon, the alcohol evaporates and what you have left is a vapid liquid. Should a fragrance not be stored in a cool, dark place, the fragrance may last for a shorter period of time.
In addition to how long perfumes should last, keep an eye to ensure your perfume has not expired. A tried and tested way to see if a perfume has expired is by spraying some onto a bit of paper and if you can smell an off-note. Also look at the colour of the perfume, has it got darker or have a yellow tint? If so, it means that the fragrance has oxidised. Perhaps ask a friend to have a sniff and tell you what they think. If they agree with you, it is time to throw it away.