Hope to never need them or get audited, but I've got all the records for each year if I ever need them.

A lease audit has always been a part of the purchasing process but now more than ever it matters since problem tenants cannot be removed. 

In my personal opinion, 24 months is a very conservative hold time because it straddles three tax years and if audited, you can clearly show your intent to hold.

My concern is tracking the time in case we get audited.

The actual percentage of people that get audited is tiny. 

The IRS just received a LOT OF FUNDING this year with the intent to increase audits.  

It is right in the Audit Techniques Guide (ATG).

Thus, it now more important than ever to ensure you are utilizing professionals that provide adequate documentation and audit defense for all real estate tax deductions and credits that are on your tax return.