My sister's house in Missouri was unheated for a while and the pipes froze. So I spent a month repairing everything: installing the water heater, adding an electrical heater to the pipes, and a LOT of time slithering around in a three foot crawl space under the house. That was in 2005, and only last month did one of the pipes give out. My sister is pretty much deaf and could not hear the water running. But this time it was not due to a freeze. I learned how to replace old steel and zinc pipes with plastic, how to thread pipes, and how to install and/or flush out all the faucets. Every one of them was somehow full of grit and leaked.
I have also replaced a lot of plumbing in my house here in Miami, which was built in 1947. I have lived here since 1977.
I do not believe I have given anyone bad advice so far, but perhaps you could let me know. I am so far only a novice plumber, and perhaps constructive criticism could be helpful.