How to store perfume so it keeps its scent
A perfume changes slowly over time, and where you keep the bottle has a lot to do with how slowly. Heat, light and air all speed the change up. Keep them away from the bottle, and the scent you wear later stays close to the scent you chose.
Keep it cool
Heat is the first thing to avoid. A perfume kept warm changes faster than one kept cool, and swinging between hot and cold is hard on it too. In a city as hot as Saigon, that rules out a windowsill, a shelf above a lamp and the inside of a parked car. A drawer or a wardrobe shelf, away from the window, does the job.
Keep it in the dark
Light does similar damage, and direct sunlight does the most. A bottle left on a sunny shelf can turn darker in color and smell flatter than it did. The box your perfume came in is the simplest protection. If you like to see your bottles, put them on a shelf the sun never reaches.
Keep the air out
Air slowly changes a perfume too. A spray bottle keeps most of it out, so leave perfume in its own bottle and pour some into a smaller one only when you travel. If your bottle has a stopper or a screw cap instead of a sprayer, close it firmly after every use.
Keep it out of the bathroom
A bathroom looks like the natural place for perfume. It is also warm and damp, and it heats up and cools down every time someone takes a shower. The bedroom is a better home for the bottle.
When you travel
Travel exposes a bottle to more heat than it meets at home. A suitcase left in a car or out in the sun gets far warmer than your room. Take a small bottle, wrap it in clothing in the middle of your bag, and leave the large bottle at home in its box. When you arrive, find it a drawer on the first day.
How to tell a perfume has changed
Look first, then smell. The liquid may have turned darker or cloudy. When you spray it, the first minutes may smell sharp, sour or flat where they used to smell bright. A perfume that has changed this way does not change back. The change comes slowly, so it helps to remember how the scent smelled in its first weeks. Many perfumes also carry a date or a shelf life on the packaging, so check that as well.
One more habit
NOTE suggests one more habit, which is to wear your perfume. A bottle you reach for every day is usually finished before time has much chance to change it.