This last item can be tricky. Some state laws create implied warranties such as the "implied warranty of merchantability" and the "implied warranty of fitness for a particular purpose" — even if a written warranty is not offered. These state laws say that a product must do what it is supposed to do, and do it safely. They also say that if you make any special performance claims, your product has to live up to them. For example, a vegetable slicer/dicer must slice and dice vegetables, and an ab exerciser must exercise your abdominal muscles.

Most written warranties attempt to limit the duration of implied warranties and disclaim liability for consequential or incidental damages. If your product breaks, you don't want consumers claiming reimbursement for incidental damages, such as the postage necessary to return the product or for the gas he or she used driving it to the post office. The Magnuson-Moss Act says that anyone who does attempt to limit implied warranties must disclose in the warranty that some state laws do not allow such limits. As attorneys who frequently review warranties, we see broad boilerplate language that clearly violates the Act much more often than we would like to admit.

Putting together a warranty template that complies with the law is more than half the battle, but there are a host of other warranty-related requirements you need to know about. For example, the Federal Trade Commission (FTC) has a rule providing that you must tell customers how they can obtain a copy of your warranty to read before they buy the product (quick fix: post a copy on your Web site). The FTC's "Guides for the Advertising of Warranties and Guarantees" discusses, among other things, what it means to say that a warranty is a "lifetime" warranty.