QF can be heated and cooled as many times as needed, they say. It does not have to be stored in a freezer. I think it was said that the shelf life is 18 months, 2 years or 3 years, depending on which site you read.

Edit: Inside the box is a piece of paper, which (on mine) indicated the month and year it was made. I'm sure that's when the shelf life starts, not when you buy it!