A DVD-RW is a disc that's able to be rewritten.  It holds about the same amount of storage capacity as the DVD-R.  The DVD-RW was developed by Pioneer in November of 1999.  Like many others the DVD-RW is used to store music, files and other media work on it.  There is one advantage DVD-RW as over DVD-R.  The advantage that the DVD-RW has over the DVD-R is that it can be erased and rewritten over.  Unlike others the DVD-RW can be playable in about 75% of conventional DVD players.

You can use the DVD-RW to just about 1000 times before having to replace it DVD-RW discs are usually used for volatile data, such as backups or collections of files.  DVD-RW can also read any type of DVD.  DVD-RW does not come double sided like the CD-RW does.  One side of the disc can hold up to about 4.38 gigabytes.  DVD-RW can be used just the same way as a large floppy disc.

DVD+RW and DVD-RW are just about the same.  They can both be written over and over again.  The only thing is that the DVD-RW is a little more compatible with DVD players and most DVD-ROMS.

Like CD-RW, DVD-RW is not really expensive.  Just for the fact that rewritable disc are not ever really expensive.  It all depends on how much you buy at once and where you decide on getting them from.  You can get them in just about any store like online computer stores of local stores.  It would be good to purchase some if you're the type of person who do a lot of burning and save memory off of your computer for backup data.