All smartphones do not depreciate equally. 18 months after purchase, iPhones can be sold for 53% of their original price, while Androids can only be sold for 42% and BlackBerries for 41% on average according to a study by Y Combinator second-hand price guide startup Priceonomics. The study also offered tips on memory upgrades and models for maximizing your phone's resale value.

That says it all.