One of the major factors is stress. If you are under stress and feel anxiety, this will increase your heart rate. The body generates more heat and you tend to sweat more. This can alter the effect of the perfume. Stress changes the body chemistry causing the perfume to smell different. Spray the perfume on areas where blood vessels are near, and check the fragrance for some hours to see how quickly it fades away.
Image courtesy: writers-black.blogspot.com
Diet also plays an important role in determining your body chemistry. What you eat has a great effect on how a smell suits you. Some examples are the consumption of garlic and onions. Garlic has a strong smell and it can come out of the pores and get mixed with the perfume, changing its actual smell. Onions can also cause gas and this will change the smell of the fragrance.
Image courtesy: forbes.com
Aging brings about a lot of changes in the body. As a person grows from a child to a teenager, an adult and then gets old; the hormones change. A perfume might smell good when you were younger but will not have the same effect as you age. Some other stages like pregnancy can also have an effect. Pregnant women have hormonal fluctuations and may perceive a smell differently. Also menopause and diabetes can affect the choice of perfume. So chose the fragrances wisely.
Image courtesy: webmd.com
Lastly your skin type can be a determinant in choosing a perfume. Some skins absorb the oils contained in the perfumes which make them fade quickly. Such people may have to try a lot of scents before settling on one. Some people have thin and dry skin which reacts differently to scents so they need to chose perfumes accordingly.
Image courtesy: battysbath.blogspot.com