in MN, it's 20 years old and there is no official limitations on mileage or when and where they can be driven- you just need to have another vehicle registered normally as your daily driver.
i paid $39.95 each last summer for my Regal and my 74 Monte Carlo, never need to buy tabs for those cars ever again, and don't need to run a front plate, which rally cleans things up on the front of the cars.
and just in case a cop decides to give me a hard time for driving my cars, i have printed out the applicable statutes from the web and keep them in the glovebox of each car paper clipped to my insurance cards..