@Julie NearingHi Julie  for the most part it all comes down to which method (operating as a triplex or as a fourplex) is producing more rents/income.

It is not required, but you will have to be able to segregate for taxes.Many states also require that a separate bank account be used for the security deposits.Read your tenant-landlord law, get educated, you need to confidently know your processes.

I opened a series of new accounts for my property. 1 for the combined rental income and 1 for each security deposit.

(i'll be securing the financing of it against my current portfolio with the assistance of a private lending partner. 

I might also recommend a security camera to catch people trespassing and if/ when they tear down or damage the fence.

I know people use all kinds of methods and formulas and all kinds of acronyms to try to figure out if you're getting a good deal! 

Damage, to replace vinyl etc, is likely to be relatively small of 200-300 dollars.Would you fix it, and then keep the evidence to take out of their security deposit when they choose to move out, or would you confront them with the evidence, and post a bill for the amount of the work?

A small deposit is collected to secure the client on our schedule.

Before we got prequalified I had a long conversation with our lender about our plan, which is basically to follow the BRRRR method.

Absolute convinced real estate is the long term answer to financial security.