How many times can you reuse a DVD RW?

I purchased a DVD RW device to replace my VCR. I almost-but-not-quite fill it each week and then delete it after watching.

How many weeks will it last?

Most sources claim that that a DVD-RW should last from several hundred up to 1000 burn cycles. Exactly what constitutes a “burn cycle” is a bit sketchy. Is there some reason you chose DVD-RW instead of a DVR?