Most local plumbing problems are installation defects, not wear
In housing this new, very little has had time to wear out. What surfaces instead is workmanship: a fitting that was never fully seated, a drain line with inadequate fall, a shower pan that was not tested properly, a water heater connection left slightly loose. These often appear in the first few years and frequently just after a builder warranty expires, which is the point at which they become the homeowner's problem.
