im werid with cooking, i never follow instructions to the T, so my results vary a ton. I just do everything to taste* lol

But for everything else, such as doing a valve adjustment on a motor, the first time takes twice as long as the book time for the service. the second time, it hit the book time, then the 3rd time, i realize what i really dont need to do, or little tricks to make it easier and i can do it faster than book time! Its all in practice!