Siding is your home's raincoat, and a little upkeep keeps it sealing out water and looking good. Maintenance differs by material, but the goals are the same: clean it, keep it sealed, and fix damage early.
Clean it
Wash siding once a year to remove dirt, algae, and mildew that hold moisture and look shabby. A garden hose, soft brush, and mild cleaner work for most siding; pressure washing must be gentle and angled correctly so water doesn't get behind the siding.
Seal and caulk
Check and renew caulk around windows, doors, and trim where water could get in. Keep an eye on gaps and butt joints. On wood and fiber cement, maintain the paint or stain that protects the material.
Fix damage early
Replace cracked or loose siding and repair holes promptly — water behind siding rots sheathing and framing. After storms, check for impact damage and loosened pieces.