The answer to 'when to replace leak repair' is that it's generally best to replace the roof when leaks become frequent or difficult to repair. Roof leaks that recur or require multiple patch jobs are a sign that the roof is nearing the end of its lifespan and should be replaced. Most asphalt shingle roofs last 15-20 years, so if your roof is older than that, it's a good idea to start planning for a replacement.
Regularly inspecting your roof and addressing any leaks or damage promptly can help extend its lifespan. However, once the roof reaches a certain age or the leaks become too extensive, a full roof replacement is typically the best long-term solution to prevent further damage and leaks.