How long do pipes really last under pressure?

You’re spot on about copper’s longevity, but those pinhole leaks can be a real headache—especially in older homes where the water chemistry isn’t ideal. I’ve had to chase down a few myself, and it’s never fun. PEX does make life easier for retrofits, no question. The chemical leaching thing gets tossed around a lot, but like you said, certified PEX is pretty well-studied at this point. For anything hidden behind drywall, I’d go PEX too—just less to worry about long-term. Copper still has its place, but convenience matters a lot when you’re doing the work yourself.