While editing a new question, I wanted to add the "shelf-life" tag. There is no such tag (I should know this by now, having tried to use it several times.) Eventually I found the "Storage-lifetime" tag, which covers shelf life. Shelf life is a common term that many people use, and presumably like me, try to find it within the tags available. There are many questions regarding "shelf life" on this site, I believe that having this as a synonym tag is appropriate and will make it easier for users to find the correct tag for their question.