Detectable duration needs a context
Longevity describes how long a perfume remains detectable under particular conditions. It varies with the formula, applied amount, surface and your own perception. A general claim therefore cannot predict your exact experience. A fragrance that remains noticeable close to the skin may have stopped projecting widely a considerable time earlier in the trial.
Keep a simple record of your trials
Compare samples on reasonably similar days without repeatedly reapplying them. Record when you can still detect the scent close up, and occasionally ask for another person’s impression. This helps distinguish a quieter presence from disappearance, without turning an advertised number of hours into the only measure of satisfaction or perfume quality.