You should always try to use the right tool for the job, and that is a personal question so there is no "norm" or "good practice".
In my case I prefer to use a ...
- GUI, like Sourcetree, for viewing logs, diffs, staging/discarding lots of files, staging/discarding hunks, etc.
- CLI for modifying remotes, squashing commits, pushing, cloning, etc.
Also, if you plan to break out of the box a little bit, it wouldn't hurt to know a little bit about the Git internals.
