We generally want to stick by expiration dates, especially with baby food where there can be nutrient loss, Bucknavage explains. But, we have more leeway with “sell-by” and “best-if-used-by” dates. Stores generally try to get rid of all foods nearing their sell-by date, because generally those foods won’t sell. Yet, a customer can still get a lot of value out of products beyond the sell-by date.