I had some close (though not direct) lightning strikes that fried some electronics and appliances (computer, TV, AC, modem, router, spread across several circuits) over several years / storms.
I had some electricians out to to give quotes to install a whole-home surge protector and redo the grounding, in hopes of preventing these issues in the future, and asked what else could be done. Some recommended a Megger test, and they said it would show if the wiring was damaged by the surges. They also said it was ~$150 per circuit (my panel has ~20 circuits), and I'd have to unplug everything from the circuit (including receptacles, tying together the wires in the boxes). On top of that, if anything showed amiss in the test, they said they wouldn't be able to restore the circuit until the affected wiring was replaced – potentially the entire branch circuit.
Because of the extreme cost and effort, I wound up not doing it. I haven't been able to find much information about these tests. So, my question(s) is (are), are they actually useful? When would a homeowner typically get this test done? Is it typical or recommended to meg test all of the circuits, or just some?