A leak shows up three metres from where it starts. We water-test to find the entry point rather than replacing the nearest suspicious thing and hoping.
If the honest answer is that the roof is at the end of its life, we say so and put the repair cost toward the replacement.
What a roof costs here, honestly.
A 2,000 sq ft single-storey shingle roof in Palm Beach County, tear-off included. Tile and metal are more. Every quote is fixed in writing before work starts, with rotten sheathing priced per sheet in advance so a discovery is not a renegotiation.