If possible, during rehab, address some things that will help you insurance wise later:- full upgrade of the electical- full upgrade of the plumbing- removal of any sheetrock, trim, etc with lead paint- new roof- address any drainage/leaky basement issues- hardwire smoke and CO detectorsI know not all will be able to be done but most are cheaper during a big reno and will make you a better risk for the insurance companies. 

Yes to paint and light fixtures.

Hello Friends,I am hiring a contractor to paint the interior of my Single Family home (Investment Property) in New Jersey.

It has a detached garage and workshop that has some peeling paint.

Just to echo @Gabe N. point, the world is a grayer than you always paint your corner of it.

She had several cans throughout the house as well, as if she had plans to paint even more. 

The house needed paint, interior doors, some minor clean up and it was rented. 

The duct work seems like a big variable so let's say $8k as well.That's $18k in rehab costs before any minor things like flooring / painting / fixtures.Do these numbers seem egregiously off?

If I painted the unit before they moved in, and one wall has stains and smudges all over it, they get charged to have it cleaned/repainted. 

This is a good example of how paint and finishes can add good value to a property without a major renovation.Drain venting is definitely an issue in older houses.