During my recent travels, my Jeep's odometer clicked past 100,000 miles.
Within a few hundred miles of that waypoint, I got the "Change Oil" notification. The Jeep has a CVT (Continuous Velocity Transmission), so it is a self-contained system, and no way to inspect the oil myself. The only dipstick on the vehicle is the person sitting behind the steering wheel (me). Because it is a closed system, it takes a mechanic to change the oil. I have an appointment to do that this afternoon.
Many moons ago, a mechanic told me that the "Check Engine" light that comes on periodically is to get people to have a mechanic look it over, not that there is anything wrong with the vehicle. He said there is a regular 9-volt battery on the back of the dashboard, and when that battery goes dead, the "Check Engine" light comes on. On average, the battery lasts approximately 50,000 miles of driving, so it is a good way to encourage people to get periodic maintenance done.
The reason this is not widely known is that they don't want people ignoring the warning light, thinking it is just the battery. Some people (me) have even pulled the dash and replaced the battery themselves. I had just had the vehicle serviced and knew that there was no problem. If the light had come back on, I would have taken it back to the shop to get it checked.
If you are not a mechanic, never ignore your vehicle's warning lights. It might be a simple issue like a bad sensor or broken wiring, but it needs to be checked out to prevent major problems down the road.