I keep a good store of dry, canned and frozen ingredients at all times, topping up on fresh foods to make complete meals.
Dry foods.... pasta, rice, flour (different kinds), pulses, noodles, oats, sugar, various herbs and spices, sachets of yeast, potatoes
Canned/Jar foods.... passata, baked beans, condiments (mustard, soy sauce, vinegar, ketchup, mayonnaise, stock cubes), tuna, sardines, olive oil
Frozen... minced beef/pork, chicken pieces, fish steaks, prawns, some vegetables, home-cooked large pulses (kidney beans, chickpeas) and portions of left-overs (lasagne, chilli con carne etc).
The fridge always has eggs, cheese, milk, butter, yoghurt a few cooked meats and salad items. We also have a stash of biscuits, crisps and a few chocolates.
Weekdays therefore I go with quick cook/assemble dishes.... pasta with sauces, omelettes, salads, grilled meats, stir-fries, veggie dishes.... which can be thrown together in under 30 minutes. In a real hurry I'll heat up a portion of left-overs.
Weekends I cook things that take rather longer or are more complicated. If I'm making something like a slow-cook casserole, bean broth or a chicken curry I'll make plenty and freeze what's left in little one-serving dishes.