2000 S80 Coil Issue

[OlgaK]

I am just wondering what are the most common reasons for ignition coils to go bad, besides age and wear? We replaced the first cylinder coil on our Volvo yesterday, after the cylinder started to misfire. Today, the second cylinder coil went bad. All the spark plugs were replaced just before the coils went bad.
It seems like whoever worked on the car before we purchased it created a big mess - the wiring in some parts is redone, when the air compressor is plugged in, the battery dies. We found a wooden board in place of a window regulator to keep the glass from falling haha. It's a mess...
Could a wiring issue mess up coils ( we checked the wires that go directly to the coils, and they seem just fine, but who knows)? Or, maybe, overheating?
Thank you for your time.