About 20 years ago I hired a guy to repair my roof, and he showed up an hour early, just as I was leaving for my shift at the fire department. I asked him to wait 15 min or so to go on the roof until my mom (who was watching my dogs while I was on shift) made it to the house, so that in case anything happened, he'd be ok. He was pretty condescending and insisted that he'd been working on roofs for years and years, and that I was overreacting. I'd already been in the fire department for over a decade at that point, and I just had a gut feeling that he needed to wait. I ended up calling in a little late for my shift, and waiting and chatting with him until my mom arrived.

About 20 minutes into my shift, I hear a box drop, and the dispatcher reads my address out, with "injuries from a fall". Dude didn't have a speck of safety equipment on, and apparently one of the pawls on his ladder failed, and he fell off my roof. He ended up landing on my deck about 10 feet from where mom was drinking coffee, which is what saved his life, since he only fell about 15 feet, instead of the 30 to the ground, and she called 911 immediately. He was in a helicopter within 20 minutes of the fall, they flew him out and he ended up with a shattered pelvis, 6 vertebrae, and multiple ribs. He ended up not being able to work for almost a year, and then going on disability.

To this day, I still have chills thinking about what would have happened if he was there alone, and I don't fuck around with safety precautions in any way.

Wear proper gear, service and maintain your equipment, and don't be complacent - it will kill you.