Does the quality of a CD - RW go down if you keep using and erasing it?

Question

Like a tape would?

Answer 1

Yes

Answer 2

yep

Answer 3

Not exactly, but there is a limit to how many times you can re-write a CD-RW.  With a tape, you are passing an analog signal and some noise to be recorded anew on another tape.  Over time, this noise stacks and degrades the quality of the dub.

With CDs, the content is digital, so the quality of the data will not degrade over time, but the physical media can.  So the CD-RW itself is being used up and can be damaged, but the data on it is either readable or it isn't.  That's the binary nature of digital.