Seek useful duration rather than a record
A long-lasting perfume should remain enjoyable for the period in which you want to wear it. Persistence does not necessarily mean strong diffusion, and concentration alone cannot predict your result. Define the practical need: keeping a drydown detectable close to skin may be enough without expecting everyone in a room to notice it.
Compare finalists with consistent application
Test each fragrance in similar conditions with a reasonable amount and without immediately reapplying. Record what you perceive and occasionally ask for an outside impression. General promises and other wearers’ reports can suggest possibilities, but they guarantee neither the duration on your skin nor how much you will enjoy the resulting drydown.