Brady asks, "What's the best way to protect my electronics from lightning? Should I always unplug them? How can I tell if lightning has ruined my stuff?"
We're based in Florida, land of the thunderstorm, so we really see where you're coming from, Brady.
We personally like to take every precaution to protect our expensive electronics from lightning. All of our electronics are on surge protectors and all of our computers are on UPS's - uninterruptible power supplies - which are battery backups that keep the computers running long enough to let you shut them down properly when the power goes out.
A typical lightning bolt contains about 15 million volts of electricity, and it instantly heats up the air around it to 60,000 degrees Fahrenheit. Simply put, you do not mess around with lightning. The biggest surge protector in the world will not guarantee that your electronics will be safe in a thunderstorm, but it is still a good idea to plug your electronics into one. Plus, nearby strikes can cause voltage spikes, which a surge protector will protect you against most of the time.
Now, not just any surge protector will do the job. You have to make sure that it is rated high enough to absorb that extra energy. You want a surge protector that is rated to at least 600 joules or higher (it will say this on the box and on the surge protector itself). The more devices you're going to plug into it, the higher you want the surge protector to be rated.
Unfortunately, there is not much you can do if your house and electronics are directly hit by lightning. To be truly safe, you would need to unplug everything in your home before a storm. Houses don't get hit directly by lightning that often, but when it does happen it is going to fry just about everything that is plugged in.
Direct lightning damage usually isn't subtle - things won't work or they will be obviously messed up. If there has been a nearby surge, though, it might not actually leave smoke coming out of your electronics. You might not even notice the damage at first, but then, a few days or weeks later, you'll start having inexpiable problems that never go away. If you're having ongoing trouble with your electronics after a thunderstorm, it's not crazy to think that it could have been caused by a surge.
In any event, lightning is incredibly dangerous. Your best line of defense is to unplug things when you know a serious storm is coming. When things are plugged in, try to give them some protection with an uninterruptible power supply and a surge protector so you won't be caught off guard.