Shoot everything in 30FPS or 60FPS all of the time.
This is because only very expensive cameras can truly shoot video at 24FPS, and the processing programs we have now are designed to convert higher speed videos into 24FPS "cinematic" mode. If you plan to do any serious editing and your camera can handle 60FPS for the full length of the video you'll be taking, use it. If not, use 30FPS. If you need that cinematic look of 24 frames (actually 24.9 or 25FPS in countries that use the PAL format for video), you do it in your video processing program.
Video shot at 30 or 60FPS and then converted will look
better than video shot in a 24FPS mode. Only use 24FPS for special effects once you learn what the raw video looks like from your camera.
Video frame rates: 24FPS vs. 30FPS vs. 60FPS explained