When I built my house back in '87 the only thing that I did not do was the electrical and the propane install. I wrote the exam for the Dept of Labour proving I knew what I was doing and that I could plumb my house. Skilled/licensed tradesmen can challenge the exam for other trades to do their own work ..... so I plumbed my own house. Copper hot and cold supply and ABS waste and vents. That was what .. 26 years ago? When I ordered the stock I ordered L and I got M. Oh well... anyways, during our last project where we had to redo the upstairs bathroom (toilet cracked, rotted floor, filled the ceiling with water (yes -- the ceiling was vapour barriered as the upstairs wasn't finished right away in 87. Thank God for the vapour barrier = it kept the water away from the drywall. Anyways, we ended up checking all the copper supply lines - after 25 years - almost 26 years the type M was starting to degrade. The copper began to oxidize and you could see that there were pinholes delveloping in the pipes. So I have been replacing the pipes with Type L pipe - man that stuff has gotten expensive.
A lot of plumbers up here are moving to PEX. I had one do an install for my back wall spigot with a ball valve. He used PEX. When Leo and I redid the piping, that PEX was the first thing that came out. I will not have it in my house ever. Just as expensive as copper but I don't like it nor do I trust it. Type L will outlast me and probably my kids. Be good for a very long time.
Oh yeah, when the Dept of Labour inspector came to inspect the job he said it was done better than most plumbers he knew.
It was my house and I made well over 3-400 joints with all the different runs. I only had one joint that I had to redo. It still hasn't leaked yet
I was pretty proud of that job. I still do the majority of my plumbing .. and I did all the plumbing on my residential instals.