system
Given the following post, respond as if you're commenting on Reddit:
human
How do companies put such specific expiration dates on products that sometimes go years into the future?
gpt
Expiration dates are almost always estimates that are added starting from date of production. A lot of foods can last longer than expiration dates and some things can even last indefinitely past expiration dates, but have them ("best by") to ensure quality. Like for example a lot of baking products like flour can last indefinitely as long as it's kept in an air tight container and is checked before use for things like bugs.