Why you stop smelling your own perfume
You put on perfume in the morning, and by the time you reach your desk you cannot smell it. In most cases the perfume is still there. Your nose has stopped telling you about it.
A nose gets used to things
The sense of smell pays attention to what is new. A smell that stays the same gets turned down after a while, so that new smells stand out. That is why you do not notice the smell of your own home, though a visitor notices it at the door. Your perfume, right under your nose all day, gets the same treatment.
The scent has moved on, too
A perfume also grows quieter with time. The bright top notes that greeted you in the morning have passed, and what remains sits closer to the skin. Quieter is not the same as gone. People who come near you still notice it.
How to check that it is still there
Ask someone you trust. Or leave the room for a few minutes, breathe some outdoor air, come back and smell your wrist. You can also smell the collar or the scarf you wore, a little while after taking it off. Fabric keeps a scent well, and by then your nose has had a rest.
Why spraying more does not help
When you add more because you cannot smell it, your nose soon gets used to the new amount as well, and everyone else receives all of it. This is how people end up wearing far more perfume than they realize. Decide on your number of sprays in advance, and trust it. If two sprays were right last week, they are right today in the same kind of place.
Give your nose something new
If you wear one perfume every day for months, your nose may tune it out sooner. Switching between two scents, or taking a few days off, often brings it back. Spraying a spot further from your face, such as the inside of the elbow, also lets you catch the scent now and then as you move.
When a perfume really has faded
Sometimes the scent truly has gone. Light, fresh scents pass sooner than deep ones, and heat hurries every perfume along. If the person next to you cannot smell it either, one more spray is reasonable. Before you add it, think about where you are, since a closed room asks for less.
One more habit
NOTE suggests letting another person's nose be the judge. If a friend can smell your perfume from an arm's length away, that is enough in most places.