If you are not closely tracking every subtle interface change that Apple puts into practice on iOS, macOS or watchOS, it is likely you have entirely lost sight of a smaller feature or setting before. This is because, in short, Apple likes to relocate and thereby slowly supplant features no longer withstanding the test of time. With watchOS 3, the complete renovation of the operating system and reinvention of the Side button on top of it has had a similar ripple effect for numerous older features.
Power Reserve mode has become one of such cases, a feature still of much use despite the improved battery performance on Apple Watch Series 1 and 2. It used to be as easy as holding down the Side button and swiping to activate Power Reserve, but mind you, nothing is permanent with Apple and it has been silently relocated since. In case you have been caught napping on Power Reserve, let's quickly fill you in on how to deploy the potential life saver on the latest watchOS.