The effort to repair should match the part of life the mistake disrupted.

Repair is measured by the person affected rather than by how bad you feel. A missed pickup that cost somebody an afternoon of leave needs more than an apology, and a late reply that cost nothing needs less than a long explanation. Getting the scale wrong in either direction leaves a residue: one reads as dismissive, the other asks the injured person to manage your remorse.

Ask what the mistake actually cost, in hours or money or worry, and let that size your response. Then do the thing rather than describing how sorry you are.