I spent 30 hours touching up small gouges in the walls, washing the tile floors, repairing leaky faucet, cleaning residue left on walls, light switches, and cupboards, removing trash left behind, cleaning vents, fan blades, replacing light bulbs, repairing blinds, cleaning stains from carpet, fixing broken drawer, washing garage floor, & cleaning windows.  

There are many light spots, you can see the original hardwood square perimeter design on the kitchen floor, and some pet stains are still visible.

Went back at night and no lights on or AC running.

After a year of learning and gaining experience as a Realtor and working with real estate investors, a light bulb went off in my head.

We already had siding , inside drywall, and most everything else out of the inside so it was really light like a garage. 

@Peter K. thanks, either way, code enforcement requires us to get outside ventilation..... but good pointer to check if its gas and dangerous.... that should light more of a fire on penny pinching landlords.....any tips on how to, or what to look out for when making your own ventilation?

- Change vanities, mirrors,- Change light fixtures- Change seats- Change Shower systemIf needed - change- Treat tub - how to do this??

I got a call from a good tenant . he describes how when they start the dryer all the lights dim in the house , then they will flicker for a while .  

My point is, not to discourage you from making good estimates, but don't get too hung up on math from your desk as when you visit the property/walkthrough with a GC/inspector expectations often will change even if you spend hours calculating on your own.Good example: we entered a contract on a 950 sq. ft. property last week that appeared to be CBS from our Google streetview and based on our conversations with the seller who did not have much information as she lived out of state.  

Heat/Utilities $- ( no common light bulbs ANYWHERE?)