I found that cerakote I just let sit on a shelf is good for a year. I heard about the dorm fridge year ago. So that's what I do, put it all in my dorm fridge. I had a 16oz bottle of graphite black that I had for 3 years and was still perfect when I ran out.
So long story short, If you can refrigerate it, I figure 3 years shouldn't be an issue. If you let it sit out, a year is about all you can get.
I write in bolt sharpie the month and year (ie: 01/18) I received it. First in first out is my plan