How can a homeowner recognize when a roof system has problems?

Shingles, curling, and buckling, missing shingles, shingle granules in the gutters or on the ground, leaks around chimney flashing

What are my options if I decide to reroof?

Picking a trusted and qualified contractor, type of roof you want "not all roof systems are close in price." Deciding to involve insurance company

My roof leaks, do I need to have it replaced completely?

Not always, could just be a basic repair. A qualified contractor can do proper inspection and let you know. Different case if your house has suffered major storm damage

How long can I expect my roof system to last?

Typical roof will last 20 to 25 years depending on if there are additional shingle layers under roof, proper ventilation, and type of material used