Caveat Emptor

Simply put, caveat emptor is Latin for "buyer beware."  It comes from the days when products were much simpler and much easier to inspect with the naked eye for defects.  Today, some products are so complicated that it's nearly impossible to tell if they are in good working order or not.  Many states have laws that say products must "merchantable," meaning, essentially, that they must do what they are supposed to do.  Beyond that, though, if you do not have an a specific written guarantee or warranty, caveat emptor still holds in many cases.  If you are planning a major purchase of something complicated (a computer or a car, for example), inspect the warranty carefully so you know exactly what you will be responsible for if the product should fail.