Classic-Over 40 Years old.
Antique-Over 60 Years old.
That makes it easy. Now the hard part is deciding what is collectable or worth restoring. It becomes an individual choice. Your money, your garage, your time. As there is in our time, there were cars from those periods that were average, bad and awful.
I think the final part of the puzzle is where the car fits in our lives, as a car community and as individuals. As a community, there are some that mark an era we all acknowledge. That's easy to pick them out.
Then there are cars that are significant but hold special meanings to us due to our personal history.
The queston I'd like to ask to ask one of us one day is "If you never showed this car, if you never got the pat on the back of 'Nice car' or the recognition of a 'Wow', if all you could do was drive it once a year on a quiet road where no one would see it, would you still do it? Would you do it just for the pleasure of saving a piece of history and be it's caretaker?
Truth is, I'm sure if you came across a guy who collected and restored Yugo or Trablants you'd have to question his sanity. But 100 years from now......