Maintenance of asphalt shingles can be a bit of a crapshoot. How often you may have to maintain them can depend on how severe the weather can get where you live. While there should be minimal maintenance of asphalt shingles, you’ll need to keep an eye on the flashing. If flashing on asphalt shingles comes loose or is compromised, water can seep through and cause potential damage. In time, algae and moss can potentially grow on asphalt shingles, so the possibility of having to replace some can exist down the road. However, most manufacturers have included compounds to reduce the growth.