Well, it might not ever come in handy, but I always register my stuff on their site just to prove I'm a loyal customer. As an example...I recently had my out-of-warranty DS Lite break (right hinge cracked off, I'm sure there are pics of the problem elsewhere) and they fixed it for free. Granted, I did have to argue a bit, and did specifically tell them to look at my records and see all the 'hundreds and hundreds' I'd spent on them already (which of course thanks to CAG is mostly a crock), but at the end of the day I got my DS Lite fixed for free. So it can't ever hurt, ya know.