Should you split groceries or take turns paying?
Take turns when your shops are roughly the same size and happen at roughly the same rate — the differences cancel out and nobody has to track anything. Split every shop when they are not: when one of you does a ninety-pound weekly and the other picks up twelve pounds of milk and bread twice a week, taking turns quietly hands one person most of the cost.
That is the whole decision, and it is a question about your shopping patterns rather than about how fair-minded either of you is.
Why taking turns drifts
It relies on two things being true that nobody checks: that the shops cost about the same, and that the turns actually alternate. Both fail slowly. One person starts doing the big shop because they drive, or because they are home on Saturdays, and six months later they have paid for roughly two-thirds of the food while both people still describe the arrangement as taking turns.
Nobody notices, because nobody is counting — which is the appeal of the system in the first place.
Why splitting every shop is tedious
It is exact, and exactness has a price: a decision on every receipt, and an entry every few days. Households that try to split groceries perfectly usually stop within a month, and then they are on no system at all, which is worse than the drift they were trying to avoid.
The workable version is not per-item. It is per-shop: the total goes in, split evenly, and nobody itemises the person who bought their own coffee.
The middle option most households land on
Both of you shop when it suits, both of you log the total in the same place, and one transfer at the end of the month evens it up. It has the convenience of taking turns and the honesty of splitting, and it costs about ten seconds per shop.
It also removes the only genuinely unpleasant part of taking turns, which is one person keeping a private mental tally and deciding whether to mention it.
When one of you eats very differently
Separate the shop rather than the split. Staples, cleaning, the things both households would buy anyway go in the shared total; the expensive specific thing one person eats goes on their own card. Trying to express that as a percentage is how a grocery arrangement turns into a negotiation.
Once you have agreed the split
Something has to apply it every month.
Pairly holds the rent, the bills and who pays what, splits them evenly or by income, and keeps a running total of who has covered more. Both of you see the same month.