I guess for typical driving yes, its more for the poeple out doing long circuit racing i suppose, but even then I see them as useless because youd have time to leave the car to idle for a min or two, as opposed to the usual person around here that only gets one because they dont have time to sit in the parking lot at work to let thier turbo cool down, when work is only two blocks away.

buts what is it they say and ounce of prevention is worth....(something? cant remember the rest) lol