You want to know what shape the roof is in. These pages explain when an inspection makes sense, what it should include, and what to do with the report.
Walk around the house and photograph the roof edges, vents and chimneys from the ground.
An insurer's roof inspection is mostly about how long the roof should last. You can ask what exactly was flagged, and you can get your own look first.
Look at your roof from the ground in spring and fall, and after any severe storm.
Yes, some roofers inspect for free. They do it hoping to win the repair job, so treat the visit as a sales quote, not a neutral verdict.