Okay I see your point in the comment to the first answer. Things like this often vary from state to state. Although that is a fact I have not checked. The fact that it says you can wait seven days without paying a penalty suggest that you have something of a grace period like there is with liability automobile insurance. But just because it says this doesn't mean this is necessarily so. It could just mean that you can park your car and as long as you don't drive it you still have seven days until a late registeration fine is charged. In South Carolina for example I drove my new truck on a 45 day temp tag ...I did not have the money to register it when the 45 days expired and tagged it a couple weeks late and they charged me a penalty.....The main thing here is that driving without a vaild tag is not a big infraction...it is not a moving violation like driving uninsured is. So if a police officer caught you driving with it in only a few days late...they might not charge you if you tell them you did not realise it was out. This happend to me but mine was almost a month old so they did give me a ticket ,,,I told them it was my wifes job to take care of it and also it was her car. All of which was true.
The same day they expire and you drive you brake the law so don't do it
Not at all or ever if you do not get caught