COMPLETE REWIRE.
Although somewhat off subject, many years ago I went even further down in my late widowed mother-in- law's overall opinion of me. Her light in the hall was flickering so I had a look at it for her. My knowledge of all things mains power in those days was virtually nil. I could replace a fuse in a plug, and before circuit breakers came in, repair a fuse in the house fuse box with the appropriate thickness of fuse wire, but that was it.
So I turned off the electric, took out the light bulb, and checked that the wiring to the bulb holder (pendant ?) was okay, which it was. I then turned my attention to the ceiling rose which I undid to check the wiring coming out of the ceiling. The wiring for the whole house was very old, probably being the original from 60 years before. I could see that there was a loose wire and instead of just tightening the screw, I unscrewed it and pulled the wire out completely (don't ask).
Big mistake. The insulation was so brittle it all came off like a piece of bone china breaking, and I was left holding bare wire. No problem (I thought), I'll just pull a piece of slack through and nip off the bare wire. Well as I did, the brittle insulation just kept falling off like dead leaves from a tree in autumn. I gently kept pulling but eventually there was no slack left, and just a 12" piece of bare wire disappearing into the ceiling.
Even I knew I couldn't put lots of insulation tape on and reconnect it. Well I could but it wouldn't exactly be safe. I therefore had to break the bad news to my mother-in-law that I'd have to contact a qualified electrician for her. I was there when he eventually arrived and I was half expecting what he was going to say. He checked the state of the wiring generally and advised that a complete house rewire was required. The look my mother-in-law gave me can only be imagined.
Because of the age of the house, channels had to be made in the plaster of the walls to accommodate the wiring and capping. So course, she had to get a decorator in to repaper the rooms. From then on, I never once offered to do any more jobs for her as I knew what the answer would be !