The same fragrance can smell sharp on one person and warm on another. Skin is part of the delivery system, and the variation is in the physics of evaporation rather than in perception alone.
Fragrance works by evaporating in stages
A perfume contains molecules of different volatilities. Light molecules evaporate first, heavier ones later, which produces the familiar progression from opening to base.
What reaches a nose at any moment is whatever is currently evaporating, so the composition in the air changes continuously.
Anything that changes evaporation rate therefore changes the timing and balance of that progression, which is what people describe as smelling different.
Skin temperature sets the rate
Warmer skin drives faster evaporation. The opening notes burn off more quickly and the heavier materials come forward sooner.
On cooler skin the same fragrance unfolds more slowly, holds its opening longer and can seem lighter throughout.
Pulse points are recommended because they are warm, which is a deliberate use of this effect rather than a superstition.
Skin oils hold heavier molecules
Fragrance materials dissolve into the lipid film on skin, and oilier skin retains the heavier, less volatile molecules for longer.
Drier skin holds less, so a fragrance can fade noticeably faster and read as thinner from the first hour onward.
Applying to moisturised skin extends wear for the same reason, since the emollient layer gives the materials somewhere to sit.
Residual chemistry contributes
Soap, laundry detergent, deodorant, hair product and diet all leave traces that mix with a fragrance in the air above the skin.
These are usually faint individually and collectively enough to shift the impression, particularly in the first minutes after application.
Skin pH varies between people and across the day as well, and some fragrance materials shift character with it.
This is why the same bottle can behave differently on one person from one week to the next, without anything about the perfume itself having changed.
Perception is the other half
Sensitivity to specific molecules varies considerably between individuals, and some people cannot detect certain musks at all.
The nose also adapts quickly, so a wearer stops registering their own fragrance long before other people do, which drives over-application.
Adaptation is specific to the molecules being smelled, which is why a familiar scent seems to vanish while an unfamiliar one on someone else remains obvious.
Between skin chemistry and receptor variation, no two people are experiencing quite the same fragrance, which is why testing on skin remains the only useful way to choose one.