Have had a set for 8 years. Still running on original bearings. I have the CK hub tool and have done one complete strip down and rebuild in that time. I put in a new set of o-rings etc at the time, but they weren’t really needed. I suppose I clean the bearings about once every 18 months or so. The rear hub did take time to bed in from new, and required adjusting for the first couple of months (not every ride though). There’s no getting away from the fact that they cost a fortune, but looked after they will last for years.
I suppose I ought to service mine now 😳