The answer to 'when to replace ridge vent' is that ridge vents typically need to be replaced every 15-20 years, or sooner if they show signs of significant wear and tear. Ridge vents are an important part of a home's roofing system, helping to improve attic ventilation and prevent moisture buildup. Over time, the materials in the ridge vent can degrade due to exposure to the elements, leading to leaks, cracks, or other issues that require replacement.
If you notice any cracking, warping, or visible damage to your ridge vent, it's a good idea to have a professional roofing contractor inspect it and determine if replacement is needed. Additionally, if your roof is nearing the end of its lifespan (around 20-25 years for most asphalt shingle roofs), it's generally a good idea to replace the ridge vent at the same time as the roof to ensure the entire roofing system is in good condition.