Shared groceries break down for one reason: nobody can see the same list at the same time. Here’s a system that works whether or not you use an app for it — Guava’s shared shopping list (linked below) just automates steps 2 and 3.
Not a group chat thread, not separate notes apps — one list everyone can add to as things run out.
Whoever’s making a grocery run marks which items they’re covering, so two people don’t buy the same thing.
If anyone’s cooking a planned meal, its ingredients should land on the shared list without retyping them.
Track who bought what over the week and split the total, rather than Venmo-ing each other after every trip.