My friend recently lost her husband due to burns suffered in a very bad fire and you won't believe the cause. They had an old home with one of the old-style medicine cabinets. These medicine cabinets have a slot used as a razor blade disposal where the old blades fall down into the wall. Well the home must of had a lot of shavers over the years because there was quite an accumulation of the used blades inside the wall. So many used blades that the blades ended up cutting into some Romex electrical wiring inside the wall and shorted it out.
I had warned them about checking their smoke detectors on more than one occasion but my warnings had gone unheeded. As a result, the only warning they had was their dogs barking franticly that morning. Once the dog woke them up, his wife got out quickly but the husband lingered in the bedroom searching for a metal box that they kept their personal papers in. He ended up with burns over 80% of his body and died about two weeks later of a massive infection.
The fire investigators determined that the discarded blades had slowly cut into the Romex electrical cable as the family walked across that floors over the years, eventually shorting out the wires.
If you have an medicine cabinet, you need to open up the wall and see if you have a large collection of old blades. This might require cutting into your wall but it's a lot better than waking up to your house on fire. Forward this message to anyone you know with an older home.