Bob,
I had a good laugh with your "photon battery" come-back.
In addition to the camera, get the longest extended warranty you can find and make sure it has accidental damage coverage. It
will come in handy.
I find that I take anywhere between 50 and 100 (low res) pics on any given (typical) house. More if it needs a lot of work. I prefer using a camera that accepts a removable SD card so I can still download the pics after I drop and kill the camera. I also finally bought a cheap back-up camera that accepts the same card so I can continue the inspection after I pick up the pieces of my primary camera.
I have used the screwdriver that Jim recommended for years. Just lost it the other day.
I used a "yankee" screwdriver for years, but am unable to get replacement bits. I'm bummed because I
really liked the yankee.
I have also seen screwdrivers that have torx and security torx bits that store in the handle in addition to the standard phillips, slotted and square drive bits. I have yet to pick one up, though.
I disagree with Rick on the voice recorder and folding ladder. I use an aluminum extension. The folding ladders are just too darned heavy for my taste and I cannot stand folding/unfolding them. Instead of a voice recorder, I take pics and they jog my memory just fine.
I think that Rick is referring to photographing data/information plates on furnaces, water heaters, etc.
I also have clean shoes (slip-on) so I don't track mud into people's homes. Some people like the plastic things that go on over the boots.