It is a timely decision that you should take in deciding to repair or replace roofing. You do not want to replace the roof too early and waste money, but you do not want to wait for a lot of time either.
Ultimately, all the roofs wear out and require to be replaced. You do not want to do it too early, because you will waste money. But you also do not want to waste a long time waiting, because then your roof will develop leakages and expensive water damage. To get the timing correct, you should be aware of assessing the entire problem of your roof and recognize early signs of roof failure.
If most part of the roof is still in better shape, it makes a lot of sense to do spot repair. But if the roofs show signs of wear out, or if the roof is too old like 20 years, then it will be a better thing to replace the roof.
How to fix a roof?
You should check at least once a year the condition of your roofing, then you should be able to plan the required repairs in advance. Early indications of leakage are dark areas on the ceiling, peeling paint on the inside of the roofing over hangings, damp spots near fireplaces, and water stains on the pipes venting the water heater or furnace.
You can regularly repair the leakage in a roof that is otherwise not serious. This might cost you a starting price of $10 if you just want to squeeze some roofing mastic in the gap beside the chimney flashing to $1,000 to fix a leak in the roofing. If something unforeseen occurs suddenly, like the wind storm, triggering a leakage to appear, your homeowner’s insurance will possibly recover the repair costs. But you are still accountable for limiting the leakage.