Many leaks are caused by a broken shingle or a rusted nail that allowed a shingle to slip out of place. A drip now can become a flood later, and the last place you want to be on a frigid winter day is on the roof.
HOW TO DO IT:
Spot damage from the ground using binoculars, or get a closer look from a ladder at the eaves. On the roof, use a pry bar to loosen the shingles above the one that's broken. Then pry out the nails holding the damaged shingle to remove it. Slip in a new shingle that's the same width, and secure it with nails.
Catching a leak before it happens can save you $300 or more to repair a ceiling or wall and up to $6,000 for mold remediation.