Old soil question.

So I was wondering how long does soil stay good once opened? Ive always been worried that once a bag was broke open the timer started.
Like say you bought a brand new bag of Fox Farm but only used half of it & rolled the bag up with the rest of it in it for future use. How long does that soil stay fresh & the nutes pre added stay beneficial to the plant?

Most bags of soil I've ever bought came with small holes.

If you only use part of the soil, just close the top like a bag of chips.
Fold the corners in triangles and roll down from the top.

Fox farm stays good from two years after the stamp date. Make sure you buy it from a store who get's regular shipments, and not a store that buys 10 pallets at a time and then sit on it.