When I turned 18, I received a package in the mail.  It was from Gillette.  It was a Mach3 razor.  It's now more than 8 years later, and I still use this razor when I shave (which admittedly isn't very often).  This razor uses replaceable blades, which I've purchased several times throughout the lifetime of the product.  This might be the product I've owned for the longest amount of time, aside from my guitar (and my toothbrush [kidding]).  In my opinion, this was the best marketing ploy ever. #entertainment