CB Jones
Senior Master
I too change side, usually based on what the opponent is doing. A lead leg faint is a good tactic. We often practice a double kick where the first kick is essentially a feint or setup for the second kick. A lead leg side kick is the best way to stop a hard charge with a kick, IMHO. It can be powerful enough to put someone on their backside if timed right. The body should also be centered enough during/after the kick to follow up quickly with another technique. There are probably as many variations of a lead leg kick as rear leg. It is definitely a practice/repetition thing.
Its a thing of beauty when you see a sidekick to the chest lay someone flat.