Yeah, either the pipes start leaking, and it's great if you can see a puddle on the floor. But what if the pipes are behind the wall? That happened to me, and I had to spend a ton of money on repairs. By the way, I always go to Ben's Plumbing https://bens.plumbing/blog/diy-vs-professional-plumbing/, and that's one of the reasons why I'll never do plumbing repairs myself. Besides, I've already gotten used to calling them, and they've probably gotten used to coming to my house because old pipes mean constant plumbing problems, as I've realized since moving into this old-new house.