Delivered perfumes are often recommended to rest for a few days after receiving them for several reasons:

1. Temperature and Handling: During transportation, perfumes may be exposed to varying temperatures and handling conditions. Allowing them to rest at a stable room temperature helps the fragrance components settle and recover from any temperature fluctuations.
2. Fragrance Components: Perfumes are composed of different fragrance components, including top, middle, and base notes. Resting allows these components to blend harmoniously, ensuring that you experience the fragrance as intended by the perfumer.
3. Aging and Maturity: Some perfumes may benefit from a brief resting period to reach their optimal scent profile. Similar to wine aging, this resting period allows the fragrance to mature and develop its full character.
4. Separation: Perfumes can sometimes separate during transit, with heavier and lighter components settling differently. Resting helps in recombining these components for a consistent scent.
5. Aerosolization: When a perfume is sprayed immediately after delivery, it may not represent its true scent due to the initial burst of volatile top notes. Resting allows these top notes to evaporate, revealing the perfume’s true character.
6. Personal Preference: Some individuals prefer to let their newly acquired perfumes rest to ensure they experience the fragrance at its best, especially if they are collectors or connoisseurs.

While not all perfumes require resting, it is a common practice among enthusiasts and collectors to ensure they enjoy the fragrance in its most accurate and balanced form. However, some modern perfumes are designed to be ready to wear right out of the bottle, so it’s a matter of personal preference and the specific characteristics of the fragrance.