I have a great realtor who can diagnose a house with the best of them.

He was diagnosed about three months after we closed on the property.

I've never heard of a GC removing the cover of an electrical panel to investigate the circuit branches, which could help diagnose (without paying for a much more expensive electrician) where the problem lies in that "Broken Light Switch".

It's sad, I have ripped out entire bathrooms for being hacked together for both homeowners and investors alike and let's just say any money saved on cheaper labor was lost and then some on having me come in diagnose the situation, demo, and rebuild. 

I even was diagnosed with a learning disability in math, despite that I believe with patience and step by step process that I will understand whatever math formula that's needed for any task, it might take a little while to get it but it will come through.

I was diagnosed with MS in college.  

They called me saying they weren't able to pay because the one tenant's mother was diagnosed with cancer and they needed to put available funds towards treatment.  

I will try listening for the leak, though I don't feel confident in my abilities to diagnose this problem very well.

They will even refer you to a phone number where the tenant gets an interview over the phone from a pyschologist and gives them a letter diagnosing their problems and prescribing a service animal.

Seems like a great way to diagnose heating and cooling issues, check your insulation, find hidden water leaks and mold, helpful to find wall studs, and look for electrical problems.I'm adding this to my wish list even if it is a doodad.