My green card doesn't have an expiration date as I've had it so long. What happens if I use it to go from Canada to the US, will they take it from me? When are you required to get a new one?

Green cards are usually good for 10 years from the date of issue. If you are within that, you should be good.

Green Cards issued between 1979 and 1988 do not have expiration dates and do not need to be renewed at this time. USCIS will develop a plan for replacing these cards in the near future.