Unlike every other two-wheeler I've ever owned, the owner's manual for the C650GT simply specifies "Annual service." Compare that to my TMAX which had a recommended 4,000 mile service interval, but an oil change interval of 3.000 miles (there was a warning light to "remind" you that, when it first came on, causing me a bit of panic because I thought it was a low pressure warning), and a belt replacement interval of 12,600 miles. That all adds up to a LOT of servicing! I might change my oil at 6,000 mile myself if I put on more than that in a year (which, going by my past record, is almost a foregone conclusion) but other than that, I'm not at all concerned about service costs.