Practice is important, but mostly for speed. If you could pay me minimum wage or a master normal prices to do electric work, you are money ahead paying the master even though the quality of work is the same in the end. I've done enough electric to know how to do pretty much anything, but it will take me much longer as I don't know all the shortcuts, I'll spend more time going to find the right tools (which would be in the belt of the master). I won't think that an outlet also needs a.cover and so be back to the store several times.
In the end either way the job is done right, but I know how much slower I am. I could get faster with experience, but it isn't worth my time.