Baking soda does not go bad.
Although baking soda does not go bad the baking soda can lose it's potency overtime.
But the baking soda remains safe to use for baking or for anything else for basically forever.
You can use older baking soda to clean things with or even clean car battery terminals with if you don't want to bake with it.
The older baking soda can also be used to absorb odors in the kitchen, fridge or anywhere else.
But you can safely use the older baking soda for baking no matter how old it is as long as it has no bugs or anything in it.
Baking soda can last for many years well past it's expiration date.