It is said that lightening never strikes the same place twice. That was proven incorrect at our home. We had a 70’ Sycamore tree that was nailed by lightening. The next year it was dying, so we had a tree trimmer out, who tied a ribbon around the tree, marking it for removal. Between then and the removal date (a couple days later), the tree was struck again. The marking ribbon around the tree evaporated. Plus, it wasn’t like the Sycamore was a lone tall tree. Surrounding it, were dozens of equally tall trees.
The initial lightning strike to the Sycamore, did little damage. Other than a PC’s Ethernet card, nothing else was harmed.
With the 2nd. strike to it, we weren’t so lucky! The strike took out many items, including blowing an irrigation controller off of the garage wall. Not the least of those items, was a custom $10K DAC and a $5K pre-pro. Our insurance paid it all (of course, minus our deductible). The payment process was fairly painless and the angst was minimal. Our homeowners insurance didn’t have a rider for our expensive audio equipment, because none was needed. I’ve found that to be the case here in the U.S. If one has a decent homeowners policy that pays for the home’s value, plus the home’s possessions, all audio equipment — including custom and expensive audio components — are covered as long as replacement cost doesn’t exceed the possession maximum amount.
Thus, I’m not too terribly concerned by the frequent thunder storms we have here in the Midwest. And for me and our experiences, leaving equipment plugged-in (on or off), isn’t a worry regarding power surges of the severe lightening kind.