I usually make 2 big shopping trips a month and then a few smaller ones usually just for produce or those "I forgot" moments.
But we now have less storage space in our new kitchen and a much smaller fridge - so I may have to be more diligent in going once a week. It's hard to because our grocery store is 25 minutes away so there's no way to shop and get back in between naps.
How often do you shop?