I mentioned access to mechanical items and access areas need to be cleared. It was a bit vague but I guess it did get your curiosity. By mechanical items, I was speaking of the primary components that make up the home's systems such as things like the water heater, heating unit (furnace or boiler), panel box, cooling unit (Air conditioning unit or heat pump) , sump pump (if present) to name a just a few.
Areas that should be cleared would be the attic or crawlspace access panel (if the panels are nailed have the owner remove the panel OR if screws are present but removal may damage to perimeter area, ask the owner to remove the panel as well), underneath sinks (often the location of cleaners, towels), exterior doors (garage passage doors are probably the most commonly blocked door) and under enclosed decks if possible.
As an inspector, you can't expect the owners to "clear" the house of their personal belongings but access to some of these key areas are necessary in order for the "required" (based on your association's or State's Standard of Practice) items to be inspected. If there are items that as defined in the inspector's protocol that need to be inspected and are not, it is the INSPECTOR'S responsibility to either request to have the area cleared, move the items out of the way (if not a major undertaking) or indicate in the report that the specific required item or area was not fully inspected. In many cases when I've asked for an area to be cleared so I can continue with my inspection, either the owner, realtor (s) or even buyers took the time to move the items. Unless the inspector specializes in foreclosed, HUD or vacant properties, most of the houses inspected will be occupied and along with that in a "lived in" state.
The inspector should always remind the parties involved SEVERAL times over the course of the inspection, that there are limitations with any inspection and an occupied home has the obvious limitations of not being able to get to everything. Most people understand this scenario. Just remind buyers that they should take advantage of the final walk thru to view the house when it's empty. At least any obvious concerns will be acknowledged to the seller prior to closing. We always ask our clients to bring a digital camera with them and send us any photos of concern by which we correspond to them before they close.
The empty home where the inspector can get to much more of the components than an occupied home is often looked at as an easy inspection to some people because of the increased accessibility to much of the house;however, the opposite is often the case because there are more accessible components, the inspector will have more potential areas to inspect. Most inspection protocols require the inspector to inspect a sampling of components throughout the house that represents the general condition of those components in the home but more diligent inspectors will take the time to inspect as much of the house as possible to limit the level of missing something that they wish they had found. I can't tell you how many times "my gut feeling" brought me to look at something more carefully than normal only to find out that I was sure glad I did (my client is usually pretty pleased too).
Having performed about 7000 inspections, you learn to work a bit instinctively while following the protocols during the inspection in addition to reflecting on all your past experiences to keep yourself aware of the home's condition.
Remember that the inspection is always about what you're supposed to look at and whether or not is was visible and accessible. If it's not visible or accessible, then it won't get inspected...but the inspector better make sure to detail situation in the report so the client can act in an appropriate manner.