Also, if you remove them you will end up needing to replace the roof. 

Our RE attorney unfortunately died and we have not replaced him.  

He said the old iron pipe had deteriorated and he would have to cut in to the wall to replace the drain pipe.

So multiple by $300/door *12 and divide that into $50,000...and I get that you need about 14 properties to replace that $50,000 income.   

Had to replace the HVAC, Main Electrical Box, windows, Countertops, flooring, master bathroom remodel.

Did new flooring at the time as well as replaced Sheetrock with drywall, new pipes, kitchen, double pane windows, and HVAC system.Plus 5-6 years ago put a new roof.Based on 3 comps I pulled the ARV of his house is $553k. propstream says valued at $581k.

She just replaced the air conditioner, and water heater and has done nice upgrades through the house-epoxy garage floor, granite countertops, crown molding.

I assure you, watching a few YouTube videos or attending a 3 day event doesn't replace that level of experience with local, state and federal regulations.

After that I always like to call an insurance broker to get a landlord policy quote using the replacement value to see if it comes in close to the other numbers.

Now these are cosmetic changes , if the complex needs roof replacement ( $ 30k )  and building needs paint ( $ 10k ) , asphalt is cracking ( $ 7k ) new hot water ( $ 5k ) , then that ROI % return will be shot .