Distribution Groups

I have just taken over responsibility of my organization’s Active Directory. It was a collaborative effort amongst 5 indivdual Domain Admins. As you may have guessed, it is a complete mess.

I am looking for tools to help clean it up. Things that will tell me if a Distributin Group is still being used and which computer and/or user accounts are still active.

Also, how long should I hang on to old inactive accounts. Currently we do not delete accounts – just disable – and I am abit weary about that. Should I be concerned?

I have found some change management software to help control changes made but i am not sure which ones are any good. Any thought?

Thanks in advance!

Blitz