If you still have several years left on the service life of your roof and it’s showing any signs of roof algae, mold, mildew, roof moss, or lichen then you could definitely benefit from roof cleaning. Not only would you avoid spending thousands to replace it, but it will restore the health and appearance of your roof as well, allowing you roof to reach its estimated service life. You wouldn’t replace your vinyl siding due to algae, mold, and mildew stains would you? Absolutely not, you would clean it or have someone else clean it for you. Then why spend thousands of dollars replacing a roof that can be cleaned for a small fraction of the cost?