in fact it doesn't even need to be a bike mechanic,, I'm now on a Triumph, but I believe its all the same with other manufacturers, you need to use OE (original equipment) parts whilst in warranty, but not after, and the service needs to be carried out by a competent person.. Take a for instance,, my step son is a HGV Fitter by trade, but has owned and serviced, built, mended and fettled bikes since he was in his teens (now 34) I would trust him to be more competent than a bike dealership trained apprentice just out of his time.. Do not let main dealers scare you and charge the earth,, go to a local bike mechanic..
Or as suggested above , do your own oil and filter change