A few things to think about:
With time machine you need to have a drive that is at least 2-3 times the size of what you're trying to back up. If you wait until 900gb of a 1tb is used up you can't just go get another 1tb drive and start backing it all up. This is assuming you were using the initial drive for storage and backing up.
You should backup everything in your iTunes folder and not just the actual music files.
With time machine you need to have a drive that is at least 2-3 times the size of what you're trying to back up. If you wait until 900gb of a 1tb is used up you can't just go get another 1tb drive and start backing it all up. This is assuming you were using the initial drive for storage and backing up.
You should backup everything in your iTunes folder and not just the actual music files.