fragrance longevity can be affected by numerous factors, below is taken from the net:
The oiler, the better:
We’re talking about skin here. Ever heard the saying ‘Every cloud has a silver lining?’ Well, for people perpetually plagued with pimple problems, here is their silver lining; perfume lasts longer on oily skin. So, if you have oily skin, you’re in luck for you’re sure to smell good for longer! Dry skin on the other hand causes perfume to dissipate faster. If you do have dry skin however, do not be disheartened for all is not lost yet. You can improve the staying power of your perfume by applying a bit of petroleum jelly on the spots where you’re going to squirt perfume. This will make your skin oiler and cause the aroma to last longer.
Tired olfactory receptors:
Often, we think that our perfume lasts only for as long as we can smell it. So, we think that we smell really good only for a couple of minutes after spraying perfume. However, the reality of the situation is quite different because of a phenomenon called nose fatigue, i.e. your nose gets immune to a specific scent if it is exposed to it for long. But, just because your olfactory senses cannot depict the scent anymore it doesn’t mean that others around you cannot detect it too. Hence, there is no need to douse yourself in perfume every couple of hours because you can be assured that the scent of your perfume still lingers on for quite a while after spraying it, at least for others!