I'm reminded of a Linus Tech Tips video in which they built a gaming PC with the express purpose of heating a room/house. To do this more effectively, they connected a bog-standard water cooling loop to an actual radiator like you would find plumbed into an old building, instead of using a purpose built PC water cooling radiator like every other water cooled PC ever built (I guess because they either thought it wouldn't dissipate enough heat (in which case why not just use more of them?) or because they forgot those existed). They flushed the radiator with water and vinegar before putting it to work and what came out of it was... colorful. Even after flushing it much more thoroughly, after putting it into the final setup, the system did not perform anywhere near as well as expected due to the copper water blocks inside the PC getting covered in rust and stopping conducting heat. Those systems are no joke.

Copper pipes only need replacing that often if a) you cheaped out on construction and used the thinnest kind (M-type, which isn't even legal in some states), and b) you had some pressure issue along the way that left the pipes only partially full of water for a time.