I still wonder when the camera makers will build this into the body and truly automate it. If I put the camera on a tripod and aim it at an appropriate target, the camera can flip between phase and contrast as often as it wants (without my hands touching the camera and introducting vibration!) and calibrate itself. It can tell me if the target isn't high-enough contrast or if the target distance isn't great enough. If it's a zoom lens, it can ask me to run the process twice, once at each end of the range. If it's a manual focus lens, it can throw up a 100% live view and ask me to focus it manually, then compare phase mode itself - a slower iterative process, but all still in-camera.