The answer to 'when to replace roof repair' is that you generally need to replace your roof every 20-25 years, depending on the type of roofing material and local climate conditions. Asphalt shingle roofs typically last 15-20 years, while metal, tile, and slate roofs can last 50 years or more with proper maintenance.
Signs that your roof may need replacement include missing, cracked, or curling shingles, leaks in the attic, and excessive moss or algae growth. If your roof is nearing the end of its lifespan or showing significant wear and tear, it's best to have a professional roofing contractor inspect it and provide recommendations on whether a full replacement is needed.