"Can" you - yes.

"Should" you is a different question. I generally advise against that until you have experience with the MSS, have the folders duplicated and are confident the hardware is stable and you are done playing around with a lot of new Add-Ins, functions, etc. Even then I think most of us keep around old copies of all our data until we run out of space on our clients -- then we get serious about deleting those original copies! And the ones we have on CD/DVD (etc.) go first as they can always be ripped again.

My laptop got all music cleaned out and accesses it through the MSS exclusively now, but I still have copies of most of my music on my desktop. Same for photos.

...JohnBick

No, I would NOT add storage to your client. The place to add storage would be to your MSS.

Since the CDs can easily be ripped into computer files again I would certainly remove the CDs from your client at this point.

Does your MSS have (at least) two hard drives? If yes, remove the iTunes from the client when you need the space. If you only have a single drive in the MSS, I would add a disk drive to the MSS, turn on duplication, let it run week (to burn in the hardware) and only then delete the iTunes from the client. (If you have access to the iTunes "tracks" elsewhere then duplication on the MSS is not that important. But if you have to pay to download them again then the second copy saves you that expense.)

Backups are a cost-benefit trade-off. If the cost to retrieve or re-create your data (actual expense plus the cost of your time and aggravation) is less than the cost of backing it up then you don't need to duplicate the data (music in this case). Everyone's circumstances vary in this regard, especially with respect to the value of their time, so there is no "fixed" answer.

...JohnBick