My roof is old. Shingles are worn down, some are torn, and there are some nails coming through some shingles. I'm being told by some contractors there for other reasons that my roof needs immediate repair or replacement. They question they're not really answering though is why do I need to repair anything when my roof is functioning perfectly fine. There are no leaks, no bowing, no problems other than it 'being old'.
So..
What are the problems with simply having an old roof? What am I missing - why should I repair/replace my roof when it is functioning perfectly? Why should I not wait for bad weather to tear up the roof and then rely on an insurance claim to cover damages?