Depends on what you eat.
Oats, rice, peanut butter, coffee, salt, olive oil, and tabasco are staples of my road diet, and sold in packages that last 7-10 days or more. On top of that I buy bread, bananas and beans which can be bought daily.
Fair enough. I'd add that if you used tortillas as bread the keep forever and come in larger packages so they might be bought in similar 7-10 amounts.