PCX ?

[you you]

Service manuals in many cars suggest shorter service intervals if the car is driven under severe or adverse conditions: dusty roads, frequent short trips, heavy loads, extreme temperatures, pulling trailers, excessive idling, etc… Any prolonged use that wears the engine more than the odometer reflects indicates more frequent servicing.

Service intervals or changing the oil?

[you you]

I read this recomendation sometimes in manuals. I don't know exactly why. I assume it's because air filter is not perfect and some dust particles come to engine and mix with oil.
Here is example of such recomendation for suzuki http://gsx1400.pl/instrukcje/suzuki_gsx1400k1.pdf
On page 36 "when motorcycle is used in difficult conditions, dust or with extreme use of capabilites service should be done mor often".

service or changing the oil?

[you you]

Hope we are getting close

Dusty conditions, check the air filter more often and replace as necessary.

[janwer]

service or changing the oil?

Service is changing the oil and doing the rest what manual says. That implicate changing oil "too" not "or".
In my car 20 000 service is just changing the oil with filter, and that's all. With PCX most of what should to be done every 4000 km I do every day using it.
Feel free doing what you want with your machine.

[janwer]

Everytime i check throttle, idle speed (audio), battery (checking lights whey accelerating), brake fluid and system, front brake pads, brake light when parking, headlight aim when riding, side stand when parking, suspension when riding, wheels before ride.
What's left is changing oil, air filter, check valves and rear brake pads (which usually experienced driver can feel and hear when they are finished).