Re: DVD RECORDERS' RewritableDVD Discs.
I have used one at least 50 times. With DVRs the need to use a rewritable DVD is minimized so I've never had the need to test it. That is really a better way to go these days, especially for HDTV.
What is your application? If it is to use a DVD rather than a VHS tape recorder, I think a disc will outlast a tape in continuous use.