Perfume is a mixture of ingredients sensitive to light, temperature and contact with air. Improper storage can gradually change both the color and character of a composition. The best place for a bottle is a cool, dry and dark cabinet with a stable temperature.
Direct sunlight accelerates chemical processes in perfume, so a windowsill or open shelf near a window is a poor choice. High temperatures have a similar effect. Keep bottles away from radiators and do not leave them in a hot car for long periods.
The bathroom may seem practical, but frequent temperature changes and humidity do not support fragrance longevity. A bedroom or wardrobe is better, and the original box offers extra protection. Always close the bottle carefully if it has a removable cap.
A slight color change does not necessarily mean perfume is unusable. However, if the scent has become distinctly sour, flat or completely different, degradation may have occurred. Good storage conditions can keep a collection enjoyable for many years.