Rainy days are the best time to locate—and fix—simple leaks in the roof. Pay a visit to the attic to pinpoint damp areas in the insulation or on the rafters. (Hint: Look for patches that reflect light.) Mark the wet spot (or spots), then, on a clear day, head to the roof. Enlist a helper to stand near the marked spot in the attic and direct you to the shingle right above the wet spot. Keep in mind, not every leak requires a shingle replacement. For example, if the shingle is simply curled back, you can apply roofing cement to the underside of the problem shingle, then press the shingle down firmly to secure it.