The most expensive day of an outage is the one spent waiting for a component nobody expected to need. Hot-gas-path inspections are predictable enough that the parts list can be built in advance from operating history, then revised against what the inspection actually finds.
Before the outage
Equivalent operating hours, start counts, fuel history and the previous inspection report between them predict most of the scope. Long-lead items should be committed on that basis; short-lead consumables can wait for the findings.
During
Condition mapping row by row, photographed, is what allows a parts recommendation to be defended later. A finding without a measurement is an opinion.
After
The most valuable output of an inspection is not the parts list — it is the revised interval. A machine in better condition than expected earns a longer run; one in worse condition has told you something about its duty or its fuel.