AT&T is shutting down its 3G network next February and is prepared to give its customers a new phone for free lest their current one becomes useless —that is, they can't place calls over LTE. Just don't expect the carrier to go to great costs for your replacement.
In 2014, HTC rolled out the HTC Advantage, which offered a free cracked screen replacement, two years of updates, and up to 50GB of Google Drive storage space. Today, the company is going a step further. It has announced Uh-Oh Protection, which will provide one free replacement phone in the event of a cracked screen, water damage, or a carrier switch within the first twelve months after purchase.
Alternatively, if you don't get a replacement during this time frame, HTC will offer you $100 towards the purchase of your next HTC One.
Getting your replacement won't require going without a phone, either.