Most calendars contain at least one standing commitment that everybody involved has privately stopped wanting. It was a good idea in its first year. Now it runs on politeness, and each person keeps it going on the assumption that the others still care.
Those are worth finding. Not every obligation — some are load-bearing and you would keep them at any price — but the ones held in place purely by the awkwardness of ending them. One honest conversation usually turns up relief on both sides, which is a strange thing to have spent years avoiding.