How do you know whether to REPAIR of REPLACE a roof? (shingles, colors)

[shanemcguire1]

IF the damage is caught early, repair. Signs are leaks; possible dampness. An obvious sign of trouble would be broken or lifted shingles. Dark spots on the shingles is another. When looking at your roof from a distance and you notice sagging, then you have structural damage. Look also at the surface of the roof. Notice warping, loose, or missing shingles. Green colors may be rot. Any of these signs of damage require attention.

[Bergenite]

Shane, the dark stains on the shingles is algae, not a sign of failure. The green spots on the shingles is lichen growth and not a sign of failure.