A shared grocery list that actually stops double-buying

Two people buy milk on the same evening. Nobody buys eggs for a week. It's not laziness - it's that the list lives in one person's head.

What a good shared list does

• Everyone can add to it from their phone the second they notice something's low.
• Whoever buys an item ticks it off, so nobody else buys it too.
• It remembers what you always buy, so adding rice takes two taps.
• When someone pays, the cost can go straight into the flat's expenses.

Habits that make it stick

Add things the moment you finish them, not later. Keep one list for the whole flat rather than one per person. Pick a weekly shop day. And make it a rule that if you took the last of something, it goes on the list before you leave the kitchen.

Any shared notes app can do this. The reason a dedicated list wins is the nudge: someone reminding you it's your turn to shop is what turns a good intention into milk in the fridge.