Q: Keeping all my old macs authorized

1. There is no list available from your end.

2. Yes.

3. You can manually move the music to the new computer and play it there.

(123161)

hands4 wrote:

iTunes says I have three authorized computers.  How do I see which they are?

You don't.

Let's assume one of those Macs is long gone.  If I deauthorize that one, will I be able to play music I purchased while using that old one?

You cannot deauthorize "that one" if you do not have access to it or if it is not working.

You need to deauthorize all then authorize the computers you want.

See this -> Deauthorize your computer using iTunes - Apple Support

And yes you will be able to play music as it is linked to your AppleID, not the computer. And anything purchased after April 2009 will play on any computer.

What happens when you purchase a sixth Mac (with five historical and dead ones)?  Can you access music you purchased on all these Macs?  Do you have to sacrifice access to music that was purchased on one of them?

Ideally you will deauthorize a computer before you get rid of it. If not, deauthorize all then authorize what you want.

The music should be backed up and/or copied elsewher.  You may also be able to redownload it.