Apologies have a shelf life. The longer you wait, the more it costs both of you.

An apology offered early costs you one awkward moment. Left for a month, it has to cover the original thing plus all the silence since, and the silence is usually what did the real damage. The other person has spent that time deciding what your quiet meant. Waiting never softens an apology; it only adds to its workload.

If something small has been sitting unsaid, say it this week, plainly and without a list of reasons attached. Name what you did and leave out the part where you explain why it was fair.