Thats the whole purpose of a cdrw is to burn something on it, then erase it, and then burn something again. However, you can only do this so many times before you start having problems.
A lot of older CD players won't play CDRWs, only CDRs. So it really depends on where you want to play it. Most of the newer ones will play both, and you're basically in the clear with anything that will play MP3s.
