They've been sitting on my shelf at least that long.
Did you know that, unopened, marshmallows stay good for 40 months? That's more than three years, and that's disturbing. Even more disturbing to me? Worcestershire sauce is good for two years after you open it -- five to 10 years unopened.
Have a bunch of dusty items sitting in the back of your cupboard and you're not sure whether to pitch them? Check it out.