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

After the Katrina water rush here in Mississippi, I quit fooling around with soda bottles and bought 10 Aqua-Tainers at Walmart. It's a full month's supply of water for me, my wife, and our dog, and they are easy to store, durable, and the best-reviewed affordable container ($7.97 each).

And it's DONE, in one afternoon. No more asking people for empty bottles, washing, trying to store them in a reasonable amount of space, etc.

10 aquatainers for a month = 70 gallons = less than one gallon/day per "person" counting the dog as 0.5 of a person. I guess that's enough for drinking but don't count on it lasting a month if you wash anything, flush the toilet, etc. If you really want a month worth of water you might look into a cistern or other large tank (like 1000 gallons) or possibly a small swimming pool. Aquatainers are probably the best way to store 70 gallons of water.

Some people already HAVE large storage containers and don't realize or remember them. We're on a well and have the 'aerator' tank. It generally holds 250 gallons. If a hurricane is coming then I hold the float switch up so it fills the tank a lot more. It is outside so I do risk 'losing' it if it gets compromised but we have redundancy. We use that H20 for flushing toilets, washing etc.

Don't forget the water heater....IIRC 40-80 gallons depending on the size of it......

We also have 3 aquatainers (getting more) and in the 'off season' (for hurricanes) we have at least 5 cases of bottled drinking water. I've found that Wwashing the aquatiners and rinsing them well enough to drink from takes A LOT of time and diligence so we just go with bottled for drinking. We use it on a daily basis so it is constantly rotated.

Has anyone tried the Coleman 5 gallon water containers? I've got a few of the aquatainers, but I've heard of some problems with them, plus they're a little too large for me. I'm looking for a good alternative, and this is the closest I've found

Coleman 5 Gallon water container

The only thing i didn't like is the spigot does not store inside the container, so it would be easier for it to break off. But it seems to be a little bit better made than the aquatainers.