Single-pane windows, original doors, stained carpet that may hold pet odor, walls are dirty, blinds broken, floors not swept, etc.

If you want to continue trying to clean them, get a professional carpet cleaner and have them treat it with enzymes or something designed specifically for pet odors.

Cigarette burns are not "ordinary" and neither is the cigarette odor.

My house was just painted with ICI Lifemaster 2000 - The first solvent free, no VOC, low-odor interior latex paints.

Torn blinds, scratched doors, torn carpet, burned or dug-up lawn, odors, chewed trim, and more.

Also, ODOR is a huge issue.

I had a house where the shoe at the bathtub drain was leaking into the crawl and causing an odor.

Their kitchen is directly beneath mine and whenever they cook, their cooking odors travel up and become overwhelming in my unit.  

Some of the improvements include:Replacing the existing carpet with LVP (They had animals and there is a distinct odor)Replacing the acoustic drop ceilings (They painted the existing drop ceiling black)Removing a sliding glass door and replacing it with a french door for rental entranceReplacing the existing fluorescent lighting with can lightingReplacing painted wood panel with drywall, finishing, and painting said drywallMoving walls around to block off some areas and to make some areas biggerAdding a kitchen, which include cabinets, sink, range, and maybe a dishwasherCreate a path leading from my driveway around the backyard to the basement entrance.My space is about 1200 SF and I mentally prepared to spend about 15K to redo the basement to an acceptable quality level.

New blinds are cheap, smoke odor can be fixed by new paint/flooring and/or an ozone machine.