Is Repentance Only For Sinners?

The Holy Prophet (peace and blessings be upon him) did tawbah (repentance) more than any other human being. And yet, we know for a fact that he never committed any sins. Is repentance a utilitarian act; an effort to get a refund for one's missteps? Or is it something much more: a means of gaining true nearness to God, for sinner and sinless alike?