Electronic Wiz, thanks so much. You the man/woman. Is that to say that smoke detectors of the modern era have dates on them so that if this smoke detector does not then one can assume it is more than 10 years old? When did smoke detectors begin carrying dates, and where is the date normally noted? I see nothing on the back of the unit other than Sunbeam information and UL information. Unfortunately all I have is a photo of the back panel with all of the information that is contained on the back being clearly legible, but no date. Thanks man!