When I’d send out my bird dogs, I always told them to look for houses that had tall grass, lots of mail on the front porch, obvious signs that he house needs repairs, and especially needed roof repairs. Signs that a roof needs to be replaced are curled up shingles or blue tarps covering leaks.
If the owner could afford to get their roof fixed, they would. If they cannot afford to get their roof fixed, it is a potential deal.
You can also TRADE roof repair leads to roofing companies in exchange for them sending you all the people who cannot afford to get their roof fixed. Win -Win for both of you.