To each his own, but I'd say committing once a day. That's unless I'm wrong in thinking that doing so means your commits are quite big and could be broken up into smaller, more manageable changes.
Personally, I like it when `git diff` displays only one or at most three screenfuls of changes that haven't been committed.
Maybe I'm one of those low productivity types that interview processes are trying to permanently weed out, but I rarely write more than 40-50 good lines of code per day. Commits any smaller than that would just look like code Hemingway.
Personally, I like it when `git diff` displays only one or at most three screenfuls of changes that haven't been committed.