The short answer is yes. They can certainly spoil if you are unlucky. Some hold up better than others. Guerlain, for instance, seems to be a good vintage bottle to hang on to, especially if it is sealed. It keeps very well. Also, if you are lucky enough to get an extrait, or parfum, with a little plastic plug in the top, it is usually well preserved. The lighter formulas (EDC, EDT) seem to fall apart pretty fast.