I've always kept a few months supply of food in and rotate it as required.
The best tip I can give is to only buy things you'll actually use, otherwise you're just creating waste.
I keep tinned tomatoes, baked beans, butter beans, kidney beans, soups, coconut milk, some tinned fruit, jam, honey, custard, some convenience jars of pasta, etc, sauces, pasta, lentils, dried peas, flour, noodles, rice, ketchup, tea, coffee, sugar, hot chocolate, pet food, toilet paper, etc, in.
I also include coffee whitener and dried milk as a substitute for UHT/ fresh as it has a much longer shelf life. I do also keep 5 litres of UHT milk in as well as tetrapak orange and apple juice (6 pack of each). My friends think I'm better stocked than some shops 😆
It's useful for me because I have health issues so can't always get to the shops, and it's now a habit.
I'm actually running my freezers, stores, etc, down at the moment and am stocking up again as needed.