I agree with JohnInKansas. I no longer use CD-RWs even for data backup. I used to, when blank CD-Rs were significantly more expensive, but now you can get good quality CD-R blanks for a few pence each if you shop around.

I never use very cheap unbranded CD-Rs though, because these are false economy, IME. They are often not protected on one side like the branded ones are, so the slightest scratch on the top of the CD-R can ruin the disk. Branded CD-Rs have a coating on top (usually with the brand name, etc.) which protects the disk on that side, against minor damage.