The iPhone 5 has two active replacement programs. One of them is to replace the lock button and the other is to change the battery. In both cases, only a limited number of devices are affected by these replacement programs, which have now extended their coverage for another year.
In the case of the replacement batteries for iPhone 5, only terminals sold between September 2012 and January 2013 are taken into account. Thanks to this increase in the replacement period, you can now request a battery change until January 2016, three years after its purchase.
With the program lock button replacement something similar happens. To have your iPhone 5 replaced, you must have bought it before March 31, 2013 so, if your iPhone meets the requirement, you will have up to March of the 2016 to request the replacement.
Having your iPhone or the affected component replaced is not something we will always achieve. In addition to having to comply with the range of dates in which the terminal was acquired, the serial number of the device must indicate that it is one of those affected. When you go to an Apple Store, when you go to an Apple Store, the employees will verify that there is indeed an irregularity in the proper functioning, so if despite meeting all the requirements, your iPhone 5 works well, they will not change it (I say this from my own experience ).
If you own an iPhone 5 and want check if you can qualify for one of the two replacement programs that there are assets right now, you can make the first checks from the Apple support website.