I was wondering how often do you use those specially tuned custom preset functions. Consider me a beginner but I often shoot in standard settings, only play with focus, DOF and zoom etc but never customized any special settings. Is it really necessary when most of the changes can be done in most NLEs nowadays? Please advise me on what condition do you use a certain settings. I want to learn more things. Thank you. :)

The use of custom presets depends on your camera.

For example, the XL H1's image and the XH A1/G1's image, using the default factory camera setups, can be improved using a custom preset.

With a custom preset, you can fine tune a camera to your needs.

I find myself using a custom preset on almost everything I shoot.

Others use special custom presets for special circumstances.

One example is to match the image of another camera, very useful in a two camera shoot.

Another example is to get a special image. One user felt that her XL H1's image had a magenta cast, so she created a custom preset to remove the excess magenta in her images.

Another use would be to create a custom preset for overcast days, in an attempt to bring out more colors.

There are other reasons to use custom presets. Properly implemented they are a wonderful feature.

With custom presets, you have your choice of using another users carefully crafted custom preset (a very easy thing to do), or you can create one of your own which requires a little more expertise and experimentation.