As much as I would normally get is enough for 4 people who are out of the house from 7am - 6pm every weekday.
I've been saying this for years -- I've worked full-time from home for the last 9 years. One of the first things I noticed was TP consumption went up considerably.
I didn't realize how much of my employer's TP I really used prior to that.
Then stop using ten squares to wipe your butt and restock slightly sooner than usual. Still no excuse to buy excessively more than you usually do.
But that's not the same number as the amount you should buy. Given the non-zero chance that you go out to resupply and it's sold out, you need to buy enough so that you can last until the next restock. For most people, just going out to buy it sooner than they normally would is likely enough to give them leeway. However, that still means they will have more stashed than they normally would (since they don't allow themselves to get as low).
That's why you go out and resupply anything before you run out of anything, that way you can retry later.