The inspector performs an initial site evaluation. Then the inspector takes you on a tour to point out the assets as well as any potential problems. Pay attention, watch, ask questions and learn. A thorough inspection can find problems related to water entry, roof leaks, insect infestation, unsafe wiring, failed septic systems, poor plumbing, wet basements, mold and mildew, and safety hazards.
At the end of the inspection, you receive a written report detailing all the findings. The report should contain photographs and descriptions of any damage or defects found during the inspection as well as details on the location of damage. Pictures help you understand the scope and location of the damage, and visual proof makes it easier to get repair estimates.
So how can an inspector have expertise in so many different things? The simple answer is: Some don't. That's why it's important to check an inspector's background and references.
Most home inspections are thorough, but even the best inspectors might not catch everything. The condition of the home is the 'snapshot' of that day. The home inspector is not going to find every possible thing wrong or that could go wrong. That's an unrealistic expectation.