updated 12:35 pm EDT, Tue April 22, 2014
Credit from iPad, iPhone trade-ins interchangeable
As an extension of Apple's new recycling intiatives, the iPad is now eligible for the same Reuse & Recycling program as the iPhone. People trading in an older iPad at an Apple Store can get credit towards a new model. Notably, that credit can also be applied to an iPhone; accordingly, iPhone credit can be applied towards an iPad. An iPhone and an iPhone also be traded in together towards a single purchase, but people can't bring in two iPhones or two iPads.
iPad support is reportedly limited to the US and Canada initially, and more strict in terms of quality control, blocking any cracked screens for example. Trade-ins of current or retired devices are also off-limits; the latter category includes first-generation iPhones and iPads, as well as the iPhone 3G and 3GS.
If a unit isn't eligible for credit, Apple will still recycle a device. Proper disposal of electronics can prevent unnecessary waste, as well as pollution or poisoning caused by the material being dumped into landfills.