How often does flashing need to be replaced?

How often flashing needs to be replaced depends on material, installation quality, and environmental conditions, but generally flashing should be replaced whenever the roof covering is replaced and inspected every few years for earlier failure. Galvanized steel flashing typically needs replacement every 15 to 25 years as it rusts, especially in humid, coastal, or industrial areas. Aluminum flashing lasts 20 to 30 years but can corrode if in contact with dissimilar metals. Copper flashing lasts 50 to 100 years and may outlast multiple shingle roofs, while stainless steel lasts 30 to 50 years. In practice, flashing should be inspected every 2 to 3 years for rust, cracks, gaps, or separation, and any damaged flashing should be replaced promptly to prevent leaks. When you replace your shingle roof, which is typically every 20 to 30 years for architectural shingles, you should always replace all flashing including step flashing, valley flashing, drip edge, and vent pipe boots, as reusing old flashing is a common source of leaks on new roofs and may void manufacturer warranties. Flashing may need earlier replacement if it was improperly installed using only caulk instead of step flashing techniques, if it shows signs of rust or holes, or if leaks occur around chimneys, skylights, or walls. Quality installation with compatible sealants extends replacement interval.