It was exhausting though... 

The landlord was a softie, he had an "on-site" guy who I think was milking him, and he was just exhausted by trying to keep up with the place.

I did send a mass text reminding all my tenants when rent was due, because the law students were so exhausted, they'd just forget to hand me the check that was sitting on their desk.  

BTW - you will also have to change the damper on the exhaust vent when you change from oil to gas; the gas gun kit might include that, but check your dimensions of the exhaust pipe to be sure it will fit if included.

However, every single post is touting how many units he owns, cash flow per month, and net worth goals.I would be probably be exhausted if I advertised my cash flow and net worth in every post haha.

A key to this definitely screening tenants up front, exhaustively so.

I only cheated on the lower 1/2 bath with a code compliant AAV.We did all the work ourselves so labor was just the fun of doing it.Cost of materials: Main Bath about $2k, 1/2 baths about $225 each from my spreadsheet.We got most of the materials on sale at Lowes: Good quality fiberglass Bath tub $125 (small chip hidden by tile) the toilets $35/each (both non-stock returns), double vanity $175  (side against wall damaged).All the shower stall & floor porcelain tile 75cents/sq ft from auction, Pex, PVC & fittings $185, all elect $100, 1/2 bath vanities $35 each (slight side damage hidden) Lighting $75, all mirrors $100, shower diverter/faucets $275, exhaust fans $30 each on sale. 

It may be likely you will need to move on if all of the counter offers have been exhausted.

I'd say research the potential pitfalls to find ways to avoid them going out of state, and exhaust your options in your neighborhood first.

Do not run humidifiers, run exhaust fan when showering, clean bathrooms regularly with solutions designed to remove mold, etc.- No trampolines, no swimming pools over 2 feet deep.