If you plan on charging your car regularly, flipping your breaker on and off would just be an additional task, and common sense tells me it would wear the breaker switch out quite easily (but I can't say if that's true. But, think about how many times you actually turn a breaker on and off! Rare for me unless something trips). I personally keep my breaker on all the time, and keep my mobile connector plugged into the NEMA outlet at all times, even when my car is not charging.