Although it may seem obvious to some, increasingly, it is not; I am sometimes quizzed by those heirs to the digital world who did not cut their photographic teeth on film cameras or even the earlier digital cameras regarding the use of manual functions such as exposure, aperture settings, and focus. Coming from the ancient world preceding greater electronic technology in cameras, it is second nature to me since it at one time was the only way available. But this is intended neither to disparage the younger crowd, nor to imply that I do not fully enjoy the increased versatility afforded by the latest and greatest technology. I am, was, in season, a hearty technology buff and often among the first to try new features whenever it was offered. I have been less so in recent years, not for want, but for practicality. I cannot always justify and even less frequently fennigle the use of the newest stuff. I might could, but I don't.
Still, I will answer this question of manual feature usage with a few examples. I am not saying that there are not other work-rounds or that these are the best ways to get from point A to point B, but in some cases it may be exactly the best way. The first case in point will default to a common automatic point and shoot with manual override capabilities and the second will be a more sophisticated camera that offers both a full range of automatic settings as well as manual capabilities.
I was going to comment about these, but is it really necessary? I rest my case. However I will add to my endorsement of a couple of other hybrid features. Manual focus with a mode that allows you to tweak and adjust minutely after the auto-focus is done, is useful--however, it does not replace completely manual focus. Here's why. What we used to call Zone Focusing, relies on either a scale on the lens barrel that corresponds to the aperture setting, indicating what is in acceptable focus at any given f/stop. It is especially useful in fast-moving photography such as sports.
It is easy to use with or without a scale on your lens. You simply manually focus on an object at about the same distance that you want to shoot a scene at--one that will fill the frame and show the action as it comes within a given range. You then choose the smallest aperture setting (largest aperture number) that provides a shutter speed that sufficiently stops the action. You then wait until the action is within that range, pan with the motion, and shoot. The farther depth-of-field provided by the small aperture opening maximizes the depth of field.
I have recently used this method to photograph dragonflies in mid-air. The reason the autofucus with manual tweaking does not work well while using this technique, is that it takes too much time refocusing and does not settle down quickly enough for you to tweak. Straight Manual Focus works best for this.
Another consideration is the exposure. Depending upon the sophistication of your camera, the exposure might best be preset for the area where you expect to take the pictures. Doing this manually may be the best choice. You may just have to experiment. If the auto-exposure is up for the task, it can really be helpful. But it may also have a hard time trying to guess what effect you are going for.
Manual adjustments to provide a good combination for freezing action versus gaining greater depth-of-field and working in lower light situations are important concepts to understand, although, increasingly, presets provide for more situations using quickly settable icons. The way I use these icons are usually not for what they were intended or suggested to be used for. but it does not matter. If you understand the concepts behind why the settings work, and/or if you experiment to discover exactly what these settings do, you can then file that info away in your mind and use them under whatever conditions they work for your needs. I use these setting to cheat for simplicity and quickness quite a lot. I like presets for this reason, although there seems to always be times when manual settings work better.