From my experience the machines are usually leased and maintained by some support company. You may not open, replace, etc. any parts yourself. When a machine gets replaced, you just have to hope they deal with the machine responsibly. However, this is not always the case. We once got a second hand machine with the last print jobs still available on the machine's RIP, ready for printing.

AFAIK, not every copier needs a hard disk. If you have a machine with advanced features such as scan to fax, etc. and esp when you connect it to a pc through a RIP, you are very likely to have a hard disk. Our machines have a minimum of 20gb hard disk space and we have auto-delete set up to delete anything older than a week/month depending on the type of document...