One question I get asked a lot is where to stop paint colour. Here are a few guidelines for a couple of different scenarios:
If the ceiling in your room goes up on an angle from a low wall, continue the wall colour upwards – otherwise it brings the ceiling too far down and makes the room look oddly proportioned.
When it comes to rounded corners, stopping the colour would create an odd line, so colour should be continued. Only stop at straight corners/edges.
A common scenario is the living/dining room combo. When both rooms share one long wall, that wall should be one colour - stopping anywhere along that wall will look choppy. If you choose, you can paint the entire wall a different colour from the other walls in the room to define space – but that wall needs to be all one colour along its whole length.