Once every two weeks.
We do not 'pop in' anywhere.
I freeze enough milk for beyond the Use By date of the fresh milk we buy.
Buy 'short term' fruit and veg to use in the first week, and 'long lasting' for the second week (white cabbage, red cabbage, a whole pineapple, oranges, sweet potatoes, etc)
Buy frozen veg - green beans and petit pois are good, leaf spinach for curries and pasta dishes.
Tinned pulses, tins of things like artichoke hearts (pasta and paella) , veg for stir fry like bamboo shoots and water chestnuts.
Freeze some bread products (packet of bagels) , packets of wraps / tortillas are long lasting, and when flour can be grabbed, use the breadmaker to make our bread.
Cheese, Greek yogurt etc all lasts.
Frozen bags of salmon fillets, cod, etc. Freeze meat.
Our freezer is three drawers in a fridge freezer, so not massive.
We haven't missed anything or eaten shoddily by shopping every two weeks.