The answer to 'which is better flashing or' is that flashing is generally better than caulking for most roofing applications. Flashing is a thin, durable material like metal or plastic that is installed around roof penetrations, edges, and joints to create a waterproof seal and prevent leaks. Flashing is more long-lasting and effective at keeping water out compared to caulking, which can dry out, crack, and fail over time.
Flashing is considered the superior option because it is more rigid, flexible, and resistant to the elements. It creates a physical barrier that redirects water away from vulnerable areas, while caulk is just a sealant that can break down. Flashing also requires less maintenance and has a longer lifespan than caulk. The initial cost of flashing may be higher, but it is a more reliable and durable solution in the long run.