In my opinion, a daily driver is just that, a vehicle which is driven daily. For instance, it would be the primary car on your insurance as opposed to the secondary car. In my case, our Suburban is listed as the primary family vehicle, my pickup is a work vehicle, and the '68 fastback and my wife's '69 Corvette are considered pleasure cars, only driven on special occasions. That's pretty much the standard answer as far as legal definition, but if you were thinking of using daily driver to describe a level of restoration, that's a "gray area" at best. I've seen some pretty ratty cars used as drivers, but I've also seen cars much nicer than mine used for daily commuters. In general, I guess most people use the term daily driver to describe a car that has presentable paint, a clean interior and decent trim, but may be lacking in the details, like underhood detailing or a spotless chassis. It would also be a safe, dependable car mechanically.