Not that long ago, motorcycles demanded frequent servicing and constant fettling to remain reliable and give their best. Nowadays, service intervals are longer and the processes tend towards straightforward replacement or computerised diagnostics and adjustment.
If your bike is relatively new - and definitely when still within warranty - your best bet is main dealer servicing. With a full service history, your bike will be easier to sell. But, with an older machine, doing the servicing yourself, or using a cheaper bike mechanic, starts to make more sense. Doing some of these jobs properly yourself gives you real satisfaction and a connection with your machine.