polybutylene pipe

Unfortunately so. You'll fix one leak and have 2 more the next week. You don't see it in houses often, usually in trailers or commercial buildings. I always reccomend repiping with copper or expansion pex. It definitely won't be cheap. They (piping industry) thought it was a miracle in the 70s and 80s. The 90s rocked their world and class action lawsuits killed most manufacturers...its actually illegal to install now.

I disagree with the above poster, I had it in a house I bought and had zero issues, owned the house for 8 years. I've done research and it depends on what you have, I had them with metal crimp rings and if you have those then there is little reason to replace unless you start to have issues.

It's one of those things, I have owned a house with PEX(which the company PEX that was installed was defective and the house had to be repiped) I've had all copper and there were leaks in the slab and had to be repiped. No issues with the poly at all.

With plumbing, an issue can always arise down the line, but why replace until that day comes?