Most fragrance manufacturers will recommend throwing away the bottle after one or three years (check the label), but since the fragrance doesn't expire in the same sense as food, sometimes it's okay to keep using the bottle for four or even five years. A 1 fluid ounce (30 ml) bottle of cologne or perfume contains 300 to 450 sprays, which will last approximately 4 months for an EDT, 6 months for an EDP, and 1 year for a perfume. An unopened perfume bottle can last three to five years if properly stored. The oxidation process is what happens with fragrances and causes the contents to darken over time.
The shade of black depends on the base notes; some perfumes can be completely darkened. I used to have a shoe fetish before my current addiction to perfumes and then I discovered that it was much cheaper to buy a quality perfume bottle than a pair of designer shoes. After measuring the contents of all my perfume bottles (many bottles were only partially full), I obtained the equivalent of (approximately) nineteen 50 ml bottles and eight 100 ml (or 1,750 ml) bottles of perfume. I really think someone should start making perfume coolers, you know, like the wine coolers they make, but instead of bottle racks inside, shelves for perfume bottles.
So I fervently went back to buying all the perfumes that I seemed to like, until I decided to stop this behavior (yes, it wasn't easy), also because I discovered a perfume that made me think that all the others I had didn't belong to me. To begin with, I used three empty 50 ml perfume bottles, from three different perfume companies, filled them with water and sprayed them until they were empty. Worst of all, after all these amazing years ahead of me, the next day, three Chanel perfumes appeared on the market ~ 1999 with the & of Balenciaga Rumba.
