Deciding if its worth repairing vs replacing a roof depends largely on two factors. 1. The age of the roof. 2. The quality of the installation of the roof. If the roof is approaching 20 years of age, it may be time to consider replacing it rather than fixing leaks as they start to spring up. If the roof is leaking frequently and it is less than 10 years old, a roofer should examine the quality of the installation. If it is installed well, and the the leak is isolated, it may be ok to repair only as needed. If it is discovered that there are major flaws built into the way to roof was put on, then leaks may become a recurring issue. This is a major consideration to go ahead with replacement sooner than later.