The standard recommendation is to service your car every 10,000km or 12 months, whichever comes first… but do you really need to service it every 12 months even if you don't drive it frequently?
I've had friends not service their Toyota/Honda for 18-24 months and it was fine.
I've had friends frequently service their BMW/Mercedes every 6-9 months but it was still a disaster.
What's the longest you've delayed servicing your car? Was your car okay?
And soon not even an oil change! Spot on though, none of the "mechanics" at the car dealers know anything and they expect people to buy new cars once their warranty is up anyway.