Keep a copy of the disclosure form, with their signatures, in their tenant file and prepare to keep them in archived storage long after they have departed.

Set up file folders for management and expenses for each property that you can use to archive your information year by year. 

The output of this system would be more than just a CMA as that relies only internet/archived data.  

I think this has been discussed a few times on BP so I would search the archives.  

If you remember that the clerk of the court's job is to archive filings, your assignment is easier if you remember that they aren't there to provide lists, per se.It's fairly easy if you pick a starting point and work backwards.

Seriously no offense @Aaron Yang, but if you have a team, why not have someone search through the hundreds of archived conversation threads about this very topic, among many other relevant ones with lots of good (and free) information? 

I try to capture enough voice mail and texts to archive so I have proof of the scope of the conversation.

Check out this article on Curbed: http://la.curbed.com/archives/2015/05/every_single...It shows that even at $15/hr, it's still going to be very difficulty to buy in LA. at that wage. 

I Googled to get some dates for when major floods were in Tulsa, and then I went down to the library and looked at the newspaper archives for those dates. 

A property management software such as AppFolio or even AMSI are really good with consolidating all of the information, keeps track of service  repairs, allots for accounting and maintaining resident ledgers, can keep record of correspondences and of course store archived information from previous residents.