You can get really good deals on used iPhones, especially if they haven’t been used for long. But there are a few things you should consider before buying a used iPhone, so that you don’t get the raw end of the deal.

Which iPhone do you want to buy

There’ll be plenty of iPhone models available for you to buy, right from the latest and greatest iPhone 5s to the three-year old iPhone 4. All these models can run the newest version of iOS, iOS 7, but they have varying capabilities. So you’ll want to evaluate all the available options, based on the features, hardware and software. As a rule of thumb, the latest generation iPhone is guaranteed to get more software updates, and hence last longer than older-generation iPhones.

Usage period

Many people sell their iPhone just a few months after purchasing it, probably because they didn’t like something about the device or the software that runs on it. Such iPhones are great for repurchase, because they’re as good as new, but you get it for a cheaper price. Generally speaking, you should avoid phones that have been used for a very long period of time.

Battery life

The iPhone battery gives 10 hours of talk time on 3G, but it has a limited number of recharge cycles after which it needs to be replaced. As the device approaches its recharge cycle limit, the capacity of the battery reduces as well. So you should be wary of buying an iPhone that has been used more than a year, unless the seller is willing to put in a new, official battery.

Condition

• While a brand new iPhone is shiny, it’ll be naive to expect the iPhone you’re buying in the same condition, without any scratches. That said, make sure that the device doesn’t have an excessive amount of scratches, a cracked screen, dents, or any water damage.
• To see if there’s water damage, check the SIM card tray of the iPhone 5s, iPhone 5c, iPhone 5, the headphone jack or the 30-pin connector of the iPhone 4/4s for a red color, which indicates liquid contact.
• It’s good if the device has a screen protector and/or a case, as it makes the screen and the body less prone to scratches and dents.
• You’d want to ensure that everything right from the screen, to the speakers and the buttons function properly, before money changes hands.

Carrier, Unlocked?

Make sure that the iPhone you buy will work on your carrier, and that it isn’t locked to a different carrier’s network. Even if the device is unlocked, you’ll want to ensure that the iPhone model you buy supports LTE on your carrier’s network. You can see the list of supported LTE networks on this page.

If you’re on a CDMA network like Verizon or Spring make sure the iPhone you’re buying doesn’t have a bad Electronic Serial Number (ESN). ESNs go bad when a device is reported lost or stolen, and a carrier won’t activate devices with bad ESNs on their network.

Is Activation Lock disabled?

iOS 7 adds a new anti-theft feature called Activation Lock that ties each iOS device to an Apple ID. When restoring the device to a fresh state, the user needs to know the owner’s Apple ID password to proceed, which can of course be a problem for you, the buyer. So make sure you tell the owner to disable Activation Lock by following these instructions.

Check warranty

Having a warranty is great, as it covers repairs and damages. To check if the device you’re about to purchase is covered under Apple’s warranty, enter the serial number on this page. Follow this instructions to find out the serial number of the iPhone.

Have you bought a used iPhone? Let us know your experience in the comments below.