I own 3 SFR rentals and would like to continue growing. 

I want to find out the age of the roof, windows, and the status of thr plumbing as well too.

The Houston economy is one of the biggest and fastest growing in the Nation/World so it is a great place to invest if you take the proper precautions.Here is one: http://www.harriscountyfemt.org/This is an interactive flood zone map.

However if you're positive this area is doing well and it doesn't have:Population decline or stagnationCompanies leaving the area with none taking its placeDeclining average incomeRising average age of populationRising tax delinquencies or foreclosures I would only take the leap if you understand these and there are still risks such as the aging property which might have a lot of deferred CapEx work which will eat up profits if not forecasted and budgeted correctly. 

Tampa/St Pete/Clearwater, its a growing area of Florida.

I was just thinking...If you find a suburb with consistent growth, growing number of jobs and diversified industries, a nearby bustling metro, talks of public transportation... would you build an airport?

You should withhold 5% - 8% for CapEx depending on the age of the property and quality of tenants.I am assuming you are using cash for the purchase and Rehab of the property since you did not include an acquisition loan.You mentioned utilities during the Rehab.  

That’s why most will do a personable handwritten letter instead of ppc.If I am just starting out in my own backyard why not target by area, gender, age...you know?

I think it would be nice to not have a mortgage payment at the age of 34 but my worry is it might be smarter to have 2 homes vs 1 in 30 years.

Cash on cash return - grow your portfolio - appreciation - monthly passive income etc...?