The belt renewal used to be two years but was increased when the Kevlar belts came in. I have seen belts taken off a three year old bike that had never been started and the belt had taken a set. Having seen the result of a belt breakage that needed new heads, pistons, rods etc it is false economy to ignore service schedules. Don't forget Ducati are desmodromic and don't use valve springs, clearances have to be set on opening and closing rockers. Problems came when third or fourth owner wanted to run one on Honda C90 money.