18. Baking Soda
Baking soda is more than just a baking ingredient—it’s a cleaning essential and deodorizer too. It doesn’t really expire in the traditional sense, though its leavening power may fade a bit over time. Even if it’s not ideal for baking after a few years, it’s still useful for cleaning or freshening up the fridge. Store it in a dry place, and it will last indefinitely. It’s one of those multi-purpose items that always comes in handy when you least expect it.