Everybody gets so much information all day long that they lose their common sense. Gertrude Stein
You too can be a home inspector. First look for strange, then ask the follow-up question of yourself.
Take for example a house with 4 x 8 particle or chip board panels being used for exterior sheathing and 1 x 4 wood planks covering the seams. Exterior is painted and appears to have no defects. What do you report? I would say...run. Run away from this property as it will drain your wallet as sure as the sun rises tomorrow. Inapproprate material for an application is obvious. Do not let a new installation or new paint blind your judgement.
It's the same as a shower stall being trimmed out with a painted 1 x 4, which too I've seen. You just know it's not right.
The follow-up question is..."What else did the home owner substitute, that I don't see?"