The belt change interval on a Monster 1100EVO is 15k miles OR 24 months, whichever comes first. Mine were 6 months overdue, and might have gone many more years and miles, don't know. I have seen what a slipped or broken belt can result in and I choose to follow Ducati's schedule.The actual change interval is at 15K (http://www.incredirides.com/schedules/ducati_multistrada1100s.pdf) and they only cost $85 for both (http://www.incredirides.com/schedules/ducati_multistrada1100s.pdf) ......
( https://ca-cycleworks.com/products/maintenance/timing-belts )
I, like many others check the belts for wear and leave them in for at least 30K. That said, unlike other bikes, the belts are EASILY accessible, setting tension is also easier ..... changing them can be done in less than 15 minutes including looking for your cup of coffee that you put down somewhere .
+1 re: CCW belts, and I have used them in the past. They are about 1/2 the price of OEM, and just as good.