"Probably" a few dozen, maybe lots more, or maybe handling
it and wear on the drive will make it hard to write or read.
For best results, don't depend on rewriting CDRW too many
times, these days even a 1GB USB thumbdrive can be had for
under $10 after rebates and is a better, more reliable
choice.
Depends on the brand as well.
I bought a batch of Memorex CDRW's and after a few writes they became
permanently fixed, ie: the data already on them could still be read but they
couldn't be erased to overwrite.
No problem with Maxell or Imation.