There are several telltale signs that your roof needs to be professionally cleaned. It's best to hire a professional as soon as you notice any indicators of wear to preserve your roof's longevity. Key signs to look for include:

• Moss, Algae, or Plant Growth: Look for moss growth, black streaks (which are often a type of black algae), or any other plant life on your roof's surface.

• Dirt and Grime Buildup: A general layer of dirt and grime can accumulate over time.

• Leaf Buildup: An accumulation of leaves, especially in the gutters, is a clear sign.

• Buildup Under Shingles: Dirt and debris can get trapped under the edges of your shingles.

• Shifting Roof Shingles: While this can indicate other problems, it can also be a sign that cleaning and maintenance are overdue.

• Comparison to Neighbors: If your roof appears significantly dirtier or different from your neighbors' roofs, that’s another sign it may be time for a cleaning.

You should clean your panels at least twice a year. It depends on your location. In dusty climates (think the Arizona desert), you may need to clean your panels more frequently. Dust can dramatically impact the electrical output. If you live in a climate with extreme weather, you may want to check your panels seasonally.

In most cases, it is best to leave icicles on your roof and allow them to melt naturally. You should only remove them if they are heavy enough to cause damage to your home or pose a safety risk to people below. Attempting to remove icicles yourself can be dangerous, so if you are concerned about immediate damage, it is recommended to hire a professional. To prevent icicles from recurring, you should address the underlying cause, which is often poor insulation. Long-term solutions include improving your home's insulation or installing roof heating coils.

The best way to clean a roof without damaging it is to opt for soft washing, or better yet, leave it to a professional roof cleaner. Soft washing involves a biodegradable cleaning solution being sprayed on the roof and gently rinsed away after it dissolves built-up residue on your shingles.