Cost. How is that foundation? If you get an inspector who has scopes that see into the walls, will they find water damage? Do you need to dig around the building and put a sealer on those basement walls? Is the basement floor sealed or will you get salts coming through with moisture? Is the electrical system modern or knob & tube? Is the space used properly or do you have old ass rooms that don't even have closets? Do you want to or have to (due to regulation) install a sprinkler system? Ventilation. Is it modern and does it work well? Can you add AC easily if you don't already have it? How is that roof looking? Location. Will any improvements be worth it and last or is this home in Detroit or the South side of Chicago.