Percocet used for pain relief is a narcotic medication and prescriptions can prevent people from getting high on Percocet without medical reason.In fact, the Percocet high feeling can get you into lots of problems.
I think the formula of the perfume itself decides how fast it will spoil. My perfumes from Britney Spears Curious and Salvatore Ferragamo went bad within a year and a half. The Britney Spears one developed some precipitation and started smelling like alcohol, while the Salvatore Ferragamo just smelled plain weird.
Expensive perfumes which are made from rare essential oils tend to last for a longer time than simple drug store scents. Also, most perfumes that you purchase in department stores contain only 33% pure perfume oil (vs. 60% in niche perfumes), and the rest is alcohol, water, butane and fillers.