well my can was almost a year and it worked fine. I say test it spray it on something and see if it is blochy or runny or dryed
This I would definitely agree. If you kept them in room temperature and don't expose the can in high heats and very colds, it can stay good for a very long time (I had old GW white that still works after 4 years). If you have not used it for such a long time, spray it at some disposable panel or wall. You may need to shake for a minute and spray, then repeat the process for about a couple times to clear any blockages.
I live in California, so we don't get colds or hots like the rest of the world.