To understand what the sun is, you need to describe it simultaneously using the language of genera relativity and quanta mechanics. We don't have a single principled, fully rigorous theory that describes the sun as a source of light and a source of gravity. Soo, there's very fewe to et to the spirit of your question. There's essentially no conditions that you bump into in your everyday life where you need quantum gravity. But the world is both quantum and gravitational. And iam a believer that there is a way of describing the world that is correct and complete, and that requires quantum gravity.