@Kevin FelmleeI like Cozy.co because I can market properties using a nice website they create per property, include a link to their application system and get credit and background checks, and collect rent via ACH deposit for free.

W. corner of lambs streetYou will want a software program that will keep track of the following:Income per building with a break down of each unit inside the buildingExpenses per building with a break down of each unit inside the buildingRent RollWhen a tenant is lateWhen lease will expireHow much your tenants security deposit was when move inTheir move in dateTenant TrackerVendor TrackerA Profit and Loss Report that is worth it's weigh in goal telling you your total Income less expenses giving you your bottom line any time of the day, time or year. 

At the end of the lease it must have a working disposal or it will come out of the security deposit.

The rent on it currently is half the market rent due to the sharp market upturn, and the security deposit is only $250.

Sounds like an auction site.. i know of one that does require the buyer's information to be inputted, with a valid credit card, with a small deposit.

In general I put down an earnest money deposit of 1% of purchase price, which is a much smaller amount.

I let her do 2 months rent (the deposit plus a month) and she clean up before she left, and we'd call a clean split, I would take utilities back over.

If your HML is keen to keep lending to you, wouldn't you still have enough cash for another 20% deposit for ANOTHER similar investment, straight away?

You should have in a contract that you will be putting up an initial deposit to make the contract legal.  

Where people have trouble with this approach is when their deposit-getting loans are NOT backed by existing equity; because Lenders do require to know how much they already owe, vs how much they're worth.