Leaks, renovations, and old age: no matter what the motivation, there never seems to be a convenient time to deal with roofing issues. So how do you know when you should simply repair your roof or invest in a whole new one?

The first, and most important, factor is age. The lifespan of roofing materials vary widely, so it’s good to know what you’re dealing with first.

Asphalt: The most common shingles in roofing, these materials typically last 15 to 20 years. New, highquality shingles sometimes claim a lifespan up to 40 years.

Wood: Made of western red cedar, cypress, pine and redwood trees, these shingles can last for 15 years or more, depending on the quality and the type of the wood.

Slate: They may be expensive, but slate roofs can last up to 100 ears.

Concrete and Clay: These heavy materials are very durable and can last up to 200 years.

Metals: Metal roofs have long been used on commercial properties but are now also being used on contemporary residences, too. Metal roofs can last for centuries.

The second factor to consider is the type of issue you are having. Many roof leaks can be repaired for the short term without having to replace the entire roof. Leaks often occur when there are problems with the flashing, the thin, continuous pieces of sheet metal or other impervious material installed to prevent the passage of water into a structure from an angle or joint. You’ll usually see this when two parts of a roof join together, where the roof meets the chimney or where the roof meets a plumbing vent. If you’re finding that there is extensive damage from moisture to the roofing layer or any interior surfaces, you should probably consider a full replacement.

Another factor to consider is the shape of your shingles. If you’re missing a few shingles, or a handful are damaged, you can replace them. If more than 30 percent of your roof has torn, split, curled or missing shingles, it’s time to add a new roof. You’ll sometimes see this suddenly after a bad hailstorm.

Lastly, if your home recently survived a major catastrophe, such as a tornado or hurricane, you might very well need a new roof. You’ll usually damage beyond what you can usually see.

Your best bet is to call reputable roofing professional. They will do a thorough inspection and give you options of what you can do to repair your roof and compare those to the cost and benefits of total or partial replacement.