Meat bought, roughly quarterly from local farm shops. I have a big chest freezer and years of practice means I know more or less what amount to stock up to. Fish is delivered to my door, roughly every six weeks, as and when I need it.
Groceries. I do a big shop every five weeks for all the ambient food that lasts. ie things in tins, packets, jars, items that can go into the freezer like bread, butter, frozen vegetables, I also buy cleaning materials and toiletries. I keep back up stock on the top shelf of every kitchen cupboard.
I plan menus a week in advance and on my weekly shop I buy perishables and anything that is needed for the planned meals that I do not already have. The system is very flexible. When DH was working he often went overseas with only a few hours warning for an indefinite time and that never cause problems.
I find shopping boring and would rather do something else. I do not shop on the internet, it is too inflexible and the value of my weekly order, is often quite low. As it is, on most weeks I am in and out of the supermarket in half an hour and can then spend my time on more rewarding activities.
My children shop several times a week, often in their corner shop. I can never understand it. They are very busy, yet spend two or three times as much time as I do purchasing everyday necessities, they also pay considerably more for a comparable basket of food.