When choosing discs to store files, you can choose between DVD-R and DVD-RW discs. These two types of blank discs have similar capacities, so you can store the same amount of data per disc whichever you chose. The main difference between DVD-R and DVD-RW is the ability to erase the contents in the latter. In DVD-R, you can only write to it once. When the disc is full, you can no longer alter its contents. In DVD-RW, you have the ability to erase the content of the entire disc and then write new files to it. You can do this up to 1000 times on a single DVD-RW disc before it fails and can no longer hold data.
Another difference between DVD-R and DVD-RW is compatibility. Although this is not such as huge problem like in the early days of DVD, you should still check the capability of your drive to avoid wasting money on discs you can’t use. A DVD-R drive is an earlier model that is only capable of writing to DVD-R discs but not on DVD-RW discs. DVD-RW drives are backwards compatible and are able to read and write to both DVD-R and DVD-RW discs.
As usual, more features usually mean increased cost; DVD-R and DVD-RW are no exceptions to this rule. DVD-RW discs typically cost a bit more than DVD-R discs. So you should examine whether you really need DVD-RW discs or if you would be perfectly fine with DVD-R discs. DVD-R discs are better if you want to create back-ups that will be hidden for years and only accessed every once in a while. If you only want to store the files for a short period of time, DVD-RW drives can save you money in the long run. A good example where you should use DVD-RW over DVD-R is for transferring files from one computer to another. Video recorders are also good with DVD-RW since you can offload the files to a computer or just delete them and then reuse the disc later.
Summary:
DVD-R can only be written to once while DVD-RW can be written to multiple times
DVD-R discs can be written on DVD-RW capable drives but not the other way around
DVD-RW costs more than DVD-R discs
DVD-RW is better for transferring files while DVD-R is better for long time storage