2-3 years is the usual shelf life of detailing products but can be longer or shorter depending on where they are stored, temps, and the product itself. since it hasn't been opened it, it should be fine. if it looks the same as the day you bought it and there isn't any noticeable differences (color, consistency, etc.) then you're good to go. it's a good idea to give detailing products (more so with the thicker ones) a good shake about once a month or so...