I gave up on CDRWs a long time ago. I found they failed after only a few rewrite cycles and as others have said, the cost of CDRs was so much lower that I used those. Also for relatively small amounts of data you could just keep adding or replacing files until the disk was full then bin it, so you didn't need all that many CDs anyway.

Now that flash drives have come down in price I use those. I have a 1GB flash drive which gives me more capacity than a CD can be rewritten many more times, you can work directly off it with no problems.