At home, I use 5 liters bottles.
Right now, I only have 7 or 8 such plastic bottles, stored in my -dark - basement.

But my stock is not well organized. I have some tidying up (?) to do...
Ideally, I would like to have a stock of 10 bottles at least on hand.
That means having 4 or 5 more, rotating, and buying new ones when only 10 are left.

As you mentioned, the expiration date is more than one, maybe even two years ahead.
So