DVD ReW are rewritable optical discs that are capable of being recorded and rewritten about 1,000 before needing a replacement. This makes dvd rewritables a great choice for less important data such as daily TV recording. These blank rewritable dvds have a standard capacity of 4.7 GB. The underlying mechanism for DVD rewritable media is in the recording layer. They do, however, come in various speeds and there are certain differences between operating a DVD-RW and DVD+RW.