FWIW, I consider mine to be a bed-and-breakfast so I leave enough food for several days' breakfast for 2 people. I charge accordingly, however.
I leave a small carton of milk (for coffee or for the local granola), a fruit basket with 2 single serving cheeses, 6 eggs from a local farm, a Brita water filter pitcher, salsa for the chips, and a stick of butter.
As others have said this is a personal decision and certainly varies with what you are charging.
One thing, if you need to boost your reviews, simply leaving some nice snacks or breakfast items will definitely do it.
We stayed at a small cabin in 2020 on an emergency basis when our water heater suddenly failed. The cabin is part of a complex owned by a small hotelier.
The cabin was ramshackle, had minimal natural light, had several non working light bulbs, and was full of drafts because the windows wouldn't close completely. I was really irritated by it.
But every morning the housekeeper brought us the two utterly delicious, generous hot sack breakfasts, and we were invited to walk to the main building for a freshly pulled espresso anytime we wanted.
So of course I didn't write that negative review on Trip Advisor.