Answering the OP: yes, it’s smart to stock up on essentials. So much stuff is still only intermittently available that if, like me, you’re trying to go grocery shopping only at 10-14 day intervals, your trip might hit a time when some essential is available, or it might not.
So my thought is, I want to have enough of X so that if it’s not available on my next two trips, I will still have enough to last until the third trip. So I want to keep at least 4-6 weeks worth of everything I regard as essential that won’t go bad in that time span.
For things that are especially hard to get (like TP), maybe more: I’ve got enough TP to last our family for about 2 months, and I’d like to maintain that margin if possible, given the the store shelves locally are still usually devoid of paper goods of all sorts.