While there is no exact lifespan that can be put on sealed ball joints, they can fail as early as  in modern vehicles, and much sooner in older vehicles. Signs of a failing ball joint may start with a sudden burst sound as a result of ball joint dismantling.
While there's no exact timeframe for when a sealed ball joint will fail, they can break down prematurely in both new and old cars.  A loud popping sound is often a sign that a ball joint is failing.