Careful work on older homes, and the driveways and walkways around them.
Pasadena is a city of wood. The craftsman bungalows that fill neighborhoods like Bungalow Heaven went up between 1900 and 1930, and a century later they still carry the same exposed beams, wide porches and painted siding. That wood does not take the pressure a concrete driveway takes, and the mature trees that make those streets what they are drop leaves and sap on everything underneath them all year.
Most of what we get called for here follows from that.
Porches and painted siding get soft washing, which cleans with solution and rinse instead of force. On hundred year old wood, force is what strips paint and opens the grain.
Roofs are the other half of it. Where the canopy keeps the sun off a north slope, moss settles in and stays. Driveways and walkways hold the tannin stains that come back with every fall.
We look at what the surface is before deciding how to clean it, because painted wood, raw wood, stucco and concrete each have a different limit. If a porch is in bad enough shape that washing would take the paint with it, we say so instead of finding out halfway through.
The order matters too. Roof first, then walls, then the concrete underneath, so that nothing we rinse off the top lands on something we already finished. On a property with heavy tree cover that single decision saves an hour.