Around here, and where we left, water can be more than sparse.
Were I bugging out, I would certainly want more than two, but would likely just grab a single ammo can containing a six pack of mags/ammo in a GI carrier, I can transfer the mags to a better carrier/location later.
Bugging out by car? As many cans as I can tuck away with the rest of the gear and food.
But realistically, 9 or 11 30 round mags hold a mess of ammo, especially when you don’t have the third setting on the safety selector.
Of course this is assuming the AR not the FAL.
Then we are talking a total of 8 mags including the one in the gun. 5 in a SA style chest rig, 2 in the pack and 1 in the rifle. And all 20 rounders.
As we have both said, its situation and location dependent.
But there’s still a limit to what one can carry. One of my group routinely carried 12-15 mags in/on him and another bag of 8-12 next to him in the hummer in Iraq. But he wasn’t walking anywhere also.
Out hunting, he only carries 2-3 total with another 40-60 boxed rounds just in case. That count is more than a little familiar, as I run basically the same.
Around town, I’m back to the 2-4 of the Push pack again. If I need more than 90 rounds 5o go to McDonalds, I don’t need that Big Mac.