My primary cameras have three "user customizable" options (C1, C2, C3). I don't use them. To me, they just over-complicate things and I like to keep it simple.

To me, those are similar to the "Scene Modes", such as "sports", "scenic", "portrait", etc. These automate far more than just exposure... limiting AF modes, only allowing certain file types to be saved, don't allow Exposure




Compensation or Custom White Balance, and many more things that I want to choose for myself. In fact, two of the three cameras I use most of the time don't even have "Scene Modes". The third has them, but not on a dial.... "buried" down in the menu.

I shoot a lot of sports, followed by some wildlife, a few portraits and macro... very few landscapes.

The only button or dial assignments I use:

1. Much of the time I have "Back Button Focusing" set up. On my cameras, that means "unassigning" AF from the shutter release button, so that only the AF-On button on the rear of the camera starts and runs AF. This allows me to leave my camera in continuous focus mode all the time, ready to shoot the vast majority of both stationary and moving subjects without having to pause to reset anything.

For the occasional landscape or macro shot I might turn off AF and use manual focus or switch to Live View, instead. I also prefer manual focus for street photography. I did a lot of that in the past, but not much recently. (I usually used lens distance scales to pre-focus manually, for very fast shots.)

2. I also have my cameras' "Set" button assigned to "call up" the last image I shot. This way I can use either of my thumbs to recall an image for review, to check focus, composition and the histogram for exposure. (I don't let the camera auto review every image... the default setup. That isn't necessary, wastes a lot of battery power and can be distracting.)

3. Also, my cameras have a "joystick" that's used to select AF point(s). I've got that set up so that when it's "clicked" it returns to the center AF point(s).

Besides those three things, most of my other settings aren't reassigments. They're selections and fine tuning for various exposure, white balance, AF-related, frame rate, Exposure Compensation, etc. features... as needed for different shooting conditions.

If I were to be using a specialized technique such as Focus Stacking or HDR, or if I were shooting video with my DSLRs, I might be more inclined to set up one or more of those C1, C2, C3 options.

Phil, Check out Steve Perry's "Backcountrygallery" website, he has some excellent information on this subject, and everything else too!! He takes you through the various things one can do, button by button, step by step, and explains all very well. Check it out, you will be glad you did. https://backcountrygallery.com/ His writing style and depth of knowledge are wonderful resources. Which camera you have would matter (I think) he is more Nikon centric, but a lot may transfer to any camera with multifunction buttons.
My $.02 mike

Phil, Check out Steve Perry's "Backcountrygallery" website, he has some excellent information on this subject, and everything else too!! He takes you through the various things one can do, button by button, step by step, and explains all very well. Check it out, you will be glad you did. https://backcountrygallery.com/ His writing style and depth of knowledge are wonderful resources. Which camera you have would matter (I think) he is more Nikon centric, but a lot may transfer to any camera with multifunction buttons.
My $.02 mike

This was the first resource that came to mind. The menus are Nikon but at least give you some ideas.

A tip is to get some small cheap memory cards (SD?) and store your settings periodically so if you screw up and panic you can reset with out reconstructing everything. Nikon has that ability so I assume all contemporary cameras do also. It has been twenty years since my mind was at peak performance during my mid twenties so that helps. Also if you use BBF I would devise a plan to quickly switch it off and back on it you hand your camera to an unwashed.