Preparation for an inspection is very important. Here is what to do;
--Uncover all access doors and clear access ways in unfinished spaces [attics, crawls, basements].
--If appropriate, pull stored items away from walls and doors [garages, basements, attics] and away from heaters, A/C units, water heaters, electrical panels or other permanent equipment.
--Clear out closets that have service panels or access doors in them.
--Fix anything which is easy but causes a lot of damage; small leaks over time = big damage.
--Fix anything that may look bad or reflect poorly on the house. This includes replacing all blown light bulbs. Sticking doors, cracked window glass and others flaws are easy to fix.
--Clear out garages, attics, basements, crawlspaces or move stored items to center of space.
--Trim vegetation around the house particularly if it is up against the siding or on top of roof.
--Replace any light bulbs that are out so I can test circuits successfully. [I don't replace bulbs.]
--Make sure water, electricity, gas are on to all parts of house. Light pilots on heaters; H2O also.
--Fix anything that is minor which may look like a major problem; a bulb out in a circuit could be an electrical circuit problem; it inspects as a "open" circuit because of the blown bulb. Same thing for an exhaust fan in a bathroom; if fan is burnt-out it will show as dysfunctional /open circuit; what is disconnected is not clear. [I don't replace fans, bulbs etc.; time?]
--Unlock any access points that may be locked; attics, basements, garages, storage rooms.
--Replace batteries in smoke and CO alarms if they don't test positively. Replace alarm if broken.
EXCEPTIONS BELOW;
--RADON; close house for 12 hours prior to the test & keep windows and doors closed.
-do not run attic fans or whole-house fans during above and during test.
--MOLD; leave house in same condition as usual. Don't try to "prepare" because you might erase the clues to problem. Behaviors, airflow, heating & A/C, cooking, living = typical.