Alex Senechal shared a video that goes over what planar geometry is, how to see it, and how to fix it and when it matters.
I see people who start out not knowing the difference between these when making hard surface and how it is important for modeling. I wanted to show the difference between planar and non planar geo, and how to fix it, why and when it matters. If anyone is interested. I need a better mic. Anyways hope some people find it helpful for hard surface modeling.