My aunt forwarded me this video of an ABC News investigation where they explained how, even though those nice, shiny tires at your local tire dealer may look purty, they may actually be dangerous. The video tells you much more than I can here, so I would encourage you to watch it. See, on the side of every tire (normally the side they put toward the inside), there is a long set of numbers, that looks like this:
The last set of numbers tells when the tire was made:
This tire was made in week 41 of 1994 (If it had been made in 2004, it would say "4104").
So next time you go in for tires, make the salesman (or mechanic, or whoever), show you that little code. They may act like you're overreacting. Big deal. Which is more important: keeping your family safe, or hurting the guy's feelings?