Originally Posted by Wildwood

Actually, store manager says 'another most confusing thing' is braking systems.
He wants a large poster to place in the store
that shows all the braking systems (within reason)
and compatible components
that are on the bikes they service.

The phrase is = it's complicated.

No rod brake parts; No standard inventory of vintage brake parts, no service on old coaster brakes, etc

Oh yeah , don't forget all the BB options in the last decade and crank compatibility.
Any headset experts want to explain the range of "standards" to customers wanting quick or cheap solutions.