Generally, there is no formal expiration date on your aggregate lifetime construction hours. However, regulatory boards look closely at your recency of experience.
If your 9,000 required hours were earned over 15 years ago and you haven’t stepped onto a job site since, a board may require you to log a small block of fresh, current hours (e.g., 6 to 12 months) under a current active sponsor before approving your challenge application. This ensures your knowledge aligns with current safety codes and modern building materials.