Now she got it repainted with 2 coats and sends me a bill of $3500 for the living room, dining room, and stairwell.My questions about paint are:1.

I do not know if it will add value, it may if it is uncommon for houses in the area to be insulated. and for $250, well worth doing, it may even help prevent any pipes from freezing in the future. as far as the electric, i do not find that price too bad, the basement will be easy for them to take care of, the 1st floor, they will have to open up the switch and outlets, tie the new wire to the knob and tube and pull the new wire up using that knob and tube wire and re install the switches and outlets, there is some labor involved and is easier with 2 workers. the lights are going to be the hardest for them to do and they may have to open some walls, i would check with the electrician on that and see if you are going to have the added cost of repair and re painting. a lot of times insurance companies will not cover you if there is knob and tube in the house and it was never disclosed to them, so it would be worth it to you for the insurance protection to have it done. over all though, it seems like a good price.

We repainted the walls and are getting all new flooring installed. 

Now... do you also need to repaint the units, install new flooring and do a bathroom or kitchen upgrade?

Install fresh drywall (where it makes sense) and repaint a nice white color.

I'm targetting homes that are about 15-20 years old and basically re-painting and re-flooring as needed.

I've been taking down wallpaper, repainting, doing some landscaping, refinished all the floors after taking up the rugs and have the plan to update both kitchens and my bath.

If it's wood, you are probably best to have it repainted.

So, after the contract was signed, this lady started making some "ridiculous" requests:  re-clean the whole place, repaint the whole property, and must  be with the paint that she approves.

I did pretty much all the work myself and did kitchen cabinets repainting and added finishes, added subway tiles to the front wall and back splash, added laminate through out the house, painted, and fixed up the yard and cleaned the privacy fence and painted the outside trim of the house and so on.