The answer to 'how to maintain fascia' is to regularly inspect and clean the fascia boards on your home. Fascia boards are the horizontal boards that run along the roof's edge, and they play an important role in protecting your home from water damage. To maintain them, you should visually inspect the fascia for any cracks, warping, or signs of rot or decay at least once a year, preferably in the spring or fall. If you find any damage, it's best to have a professional roofer repair or replace the fascia boards as soon as possible.
In addition to inspecting the fascia, you should also clean them regularly to remove any built-up dirt, debris, or mildew. You can use a soft-bristle brush and a mild detergent to gently scrub the fascia, being careful not to damage the material. Once cleaned, you may want to apply a protective sealant or paint to help prevent future damage.