Once and for all and Once for all

Once and for all adverb - In a conclusive way.

Once for all and once and for all are semantically related In some cases you can use "Once for all" instead the phrase "Once and for all" as an adverb or an adjective.

Once and for all and once for all are semantically related in final topic. You can use "Once and for all" instead the phrase "Once for all" as an adjective or an adverb, if it concerns topics such as last, finally, beyond any doubt.