EDP (eau de parfum) ,concentrated oil-based holds really well especially if kept out of sunlight,not exposed to air and constant cool temperature (Never in the bathroom!), water-based EDT or EDC (eau de toilette/eau de cologne) is not as stable and you often lose the top notes,can smell a bit off but after it's on your skin,in 20 minutes the top notes disappear anyway and you are left with pretty much the same scent as when it was made. If the bottle has been opened,kept in bathroom etc , the only use is in a vinagrette.