2 - 3 часы
Initially, the power button had stopped functioning on my sisters 4S. I attempted to replace it with a part from a different online retailer, but the repair was unsuccessful. Once I figured out that the part was defective (replaced with the original power and sensor cable), I decided to order the same part from iFixIt.
Repair went perfectly. I had completed it once before on my own 4S, so I knew my way around inside the phone.
Always buy your parts from iFixIt directly and be very organized!