Break it: While there might be some learning value for beginners, manual mode doesn’t have any practical advantage over the easier-to-use—and more intuitive— aperture- and shutter-priority autoexposure modes. In fact, we’ve seen countless shooters struggling to find the proper settings using manual, while their autoexposing counterparts get the shot before fleeting conditions change.
Think of aperture and shutter priority as speed manual: You set just one variable, and the camera will set the other based on the meter reading. If you don’t like how it looks, you can brighten or darken it with the exposure-compensation control.
When shooting landscapes, we almost always shoot with aperture priority, because f-stop is often non-negotiable—when we need f/16 for sufficient depth of field, for example. For wildlife, the converse is usually true: Shutter speed is usually crucial.
This photo: 1/500 sec, f/5.6, ISO 200 with exposure compensation of -0.3.