Also lot of insurance companies to give new quote asking for proof of new roof replacement otherwise not giving quote which concerns me as my roofs are very old replaced by previous owner or original roofs. 

If you have to replace a roof or HVAC in a few of them you are down tens of thousands of dollars.

This is evident when they express their goal as “ I want to own enough real estate to provide me a $10,000 per month income to replace my salary”.  

I manage my own property in Virginia, and my tenant asked me to replace the oven because it's burning food.

I think all the cast-iron piping would need to be replaced. 

And then they come back every two years yes.One of the smartest moves for investors is to replace original windows with vinyl and also make sure the home is vinyl sided.

If you are doing major renovations that could change someone's opinion as to the value of the rental, then you should wait until those major renovations are complete.For example, if I were painting and replacing flooring in a couple rooms, then I would advertise now.

We replaced everything.

For curtain rods, charge him replacement costs; for curtains, go to a thrift store and see if you can find some that work and charge him depreciated value. 

We put in around $30,000 to replace the roof, floors, paint and kitchen.