You can usually tell when your roof is in poor condition.
Perhaps nothing is growing on it and no evident damage exists. You're familiar with the appearance of a new roof, and yours could use some help. Basically, it doesn't appear to be clean.
2. It's Growing Algae and Moss
Moss and algae are sometimes difficult to see from the ground. When they accumulate on your roof, though, they frequently create discoloration. Naturally, if you notice moss, algae, or lichens developing on your roof, it's time to clean it.
3. It’s Streaky
Moss and algae, as previously said, can discolor your roof. When your roof has black or dark colored streaks on it, algae, along with mold, is a primary cause. Make sure your roof is clean before the algae grow and causes harm.
4. It’s Lifting
This is more visible in your roof's shingles.
Whether it's just a few or the entire roof, the shingles appear to be lifted. If you notice this, it's most likely because trash or germs are growing beneath the tiles. They've built up enough strength to literally pull shingles at this stage, and the roof needs to be cleaned as quickly as possible.
When should you clean your roof? Consider your climate and the time of year when pleasant, gentle weather is expected. If your roof is new, you may not need to clean it as often, but you should still get it cleaned every couple of years to keep it in good shape.