Customer notes that there is a gear or two that feel worn. Test ride before starting work to investigate. May be from worn chain and cassette. Found chain worn and cassette had some build up that cause poor shifting and skipping. Replaced chain. As scrub and clean cassette/drivetrain presented that the cassette had a good amount of useable life remaing. The derailleur hanger was bent beyond alignment and the rear derailleur had enough damage to the mounting bolt and return spring to require replacement and may have contributed to shifting/skipping issues as well, replaces hanger and derailleur.
Drivetrain scrub and clean. Inspect cassette to verify it needs replacement. DO Cassette does not need replacement. _KH Took cassette off and fully cleaned, shift ramps are working properly after cleaning. No sign of rolled metal or significant wear. No need to replace.