My My, This Milk Is "Zesty"

RealSimple has an eye-opening article up about food and expiration dates. I face this a lot with my cooking; never knowing when to pay attention to the date on the label or not. Here's some of the most interesting:

--Diet soda (and soft drinks in plastic bottles)
Unopened: 3 months from "best by" date.
Opened: Doesn't spoil, but taste is affected. *That's true, we've got some old Diet DP, and it just tastes weird...

--Honey
Indefinite shelf life

--Ketchup
Unopened: 1 year (After this time, color or flavor may be affected, but product is still generally safe to consume.)
Opened or used: 4 to 6 months (After this time, color or flavor may be affected, but product is still generally safe to consume.) *We're REALLY bad about this one...

--Peanut butter, processed (Jif)
Unopened: 2 years
Opened: 6 months; refrigerate after 3 months

Hope that helps some of y'all out.