Photoshop, and cd-rw question

When saving a file in photoshop, is it ok to put the quality at max ? Any downside besides having a huge file ?

And if I use cd-rw to save photos, and continue to delete files and upload files on it, will picture quality suffer ?

ive only had bad luck using rw's that i gave up on them. the regular cds are so cheap now, id just toss the disc and reburn it. I always save at max cuz i want best image i can squeeze outta my data.
only downside i can think of is slower computer speed when working on them (yeah i got only 1 gig ram).