DIY people sometimes use latex wall paint.Without photos or a move-in checklist signed by the tenant, it could be hard to prove.

If we take this route then is it a simple process or does this involve a lot of paperwork as well.

I think for the most part tenants understand situations can change and just keep it simple.

This accuracy and ability to keep simple and accurate records is because I develop my own software applications with MS Access and I develop accounting systems that are foolproof, idiot-proof and my recordkeeping systems and software has checks and balances that totally eliminate mistakes.You can do the same for 3 units with paper and Excel.

These loan products are very popular and simple to accomplish.

This makes it very simple and takes you out of the loop.If the applicant demands to know more, you point them to the letter and stop communicating.

Check it out, it is so simple to use and organize everything. 

I have a very simple clause that tenants are required to initial.

Using very simple math you can figure out it will take X properties @ Y% return in order to meet my financial goal. 

You can install it your self with Mr Cool DIY mini-split systems.