John A. Weeks III wrote:
/snip/
Copper is now going by the wayside for plumbing. The modern
stuff is called "PEX". It has been used in Europe for quite
a long time, and is now common in the US. It should be in
universal use in a few years. PEX appears to last a great
long time, decades, even in the most nasty water.

Decades? Pity the buyer of a 30 year home.