When I was in grade school, I read every Encyclopedia Brown book the library had. I think they are awesome books, and help add a few useful tricks to my observational skills. One of the stories that has stuck with me was when his dad was shopping for a television, and the local store was having a sale on their 'new' stock, and he deduces the date the televisions arrived at the store by examining the tags on multiple televisions; with the knowledge that the 'new' televisions are old stock being cleared out, they get a much better price. For years I would do the same thing with tags at stores. Sadly, that information has stopped showing up on tags where a simple barcode can be used to reference the item information in a database. Still, sometimes, items have very useful information imprinted on them, and it is worth paying attention to. The below video shows how the 'secret' 'tire age' code could save your life:
For more information about the 'age code', and how to decipher it for tires of various ages, check out this article.