[emacs-berlin] Customizations in custom.el or elsewhere?

[jman]

Hello,

quick poll to the group on how the custom.el file is supposed to be used.

I understand that custom.el is modified by `M-x customize-variable` and should not be manually 
edited (manual changes will be lost).
However I have a lot of small settings which I often comment if the variable is not quite 
self-explaining.

How do you use `M-x customize-variable`? Why should I use that instead of putting my customizationa 
in a specific .el file?

Thanks