While making exterior surfaces look newer, a good, thorough pressure wash can reduce wear and tear by removing the dirt, mold, algae, chalk, insects and weeds that break down and cause damage to wood and masonry, and degrade protective paint and stain.Pressure washing also makes outdoor play equipment more sanitary for the kids, removes plants and oil stains from driveways and walkways, and acts as the perfect prep for an exterior painting or staining project.