Thirty seconds? Five minutes? Half an hour?
Those looking for an exact number find too much advice and too little science. Olfactory recovery depends on the odor, the concentration, the time of exposure and the person. Adaptation studies show precisely this variation; there is no universal chronometer for perfumery.
The nose does not read the store clock
A light cologne felt quickly does not have the same effect as an intense fragrance sprayed several times indoors. If you kept the tape close to your face, the exposure was also greater.
The interval must respond to the state of perception.
Step away for a few minutes, breathe in fragrance-free air, and ask: Can I make out the next tape or has everything gained the same background? Has the first one lost definition? Am I trying to guess instead of feel?
!Tapes spread apart while the evaluator pauses in clean air
If the answer points to confusion, the pause is not over yet.
A practical reference, not a law
Between brief sniffs of a few tapes, a few minutes of neutral air may suffice. After an intense session, it may be best to walk, drink water, and resume much later. When everything looks the same, ending the test is often smarter than insisting.
The adaptation may be partially specific to the odor. This helps explain why you fail to notice the perfume you're wearing, but still notice another one when you enter the elevator. In sessions with similar fragrances, however, the overlap increases the difficulty.
Intensity calls for distance
Don't bury your nose in the tape. Move closer, take a short breath, and move away. To keep track of the progress, come back at longer intervals instead of sniffing continuously.
Schedule the application time. That way, you don't depend on the feeling that "enough time has passed".
The best break may be until tomorrow
There are days when the nose, the environment, or your attention don't cooperate. That's not failure. An interrupted test costs less than a purchase decided by fatigue.
Use your watch to organize, not to boss your body around. The most reliable signal is to regain contrast. When each ribbon rebounds to its own contour, the conversation can continue.
