There are a few factors that inform how long you will be aware of your fragrance. If you use the same perfume every day, your brain will pay less attention to it due to olfactory habituation. Smell, at its most basic level, is a survival tool. It’s like a sort of Snog, Marry, Avoid. Before we learned to rely on visual and audio cues, our sense of smell told us if we could eat something, mate with someone, or if we should run away screaming. When you experience olfactory habituation, that’s your brain telling you that this smell is familiar and safe and doesn’t need paying attention to. This is why we tend to notice scents that smell smoky longer than others. Your brain is wondering where the fire is.