Fragrance compounds in perfumes will degrade or break down if improperly stored in the presence of:

Heat
Light
Oxygen
Extraneous organic materials

Proper preservation of perfumes involve keeping them away from sources of heat and storing them where they will not be exposed to light. An opened bottle will keep its aroma intact for several years, as long as it is well stored. However the presence of oxygen in the head space of the bottle and environmental factors will in the long run alter the smell of the fragrance.

Perfumes are best preserved when kept in light-tight aluminium bottles or in their original packaging when not in use, and refrigerated to relatively low temperatures: between 3-7 degrees Celsius (37-45 degrees Fahrenheit). Although it is difficult to completely remove oxygen from the headspace of a stored flask of fragrance, opting for spray dispensers instead of rollers and "open" bottles will minimize oxygen exposure. Sprays also have the advantage of isolating fragrance inside a bottle and preventing it from mixing with dust, skin, and detritus, which would degrade and alter the quality of a perfume.