On that house I started at the water meter and replaced all with pex B. There were a few wall sections cut out and I had 20ft straight runs of pex which is hard to find. This house is not so bad, so I'm saving that project. I did get pipe insulation and wrap as much of the hot here as I could. I hate when you have to run the water to get it hot at the fixture.Old iron pipe… I remember trying to fix a water line at my Grandfather’s house. Each time we fixed a leak, the next joint down started leaking. I think my father and I turned a small leak into an all evening project chasing leaks down the line.