The calendar fills with agreements whose reasons have expired
Most recurring obligations outlive the situation that made them sensible, and nobody notices the moment they stop making sense.
A recurring commitment is a decision made once and executed indefinitely. That is its efficiency and also its flaw. You agreed to the monthly thing because of a project, and the project ended, and the monthly thing did not. You joined the group when you lived nearby. You took on the task when there were fewer people to share it, and now there are more, and it is still yours. None of these are anyone's fault. Recurrence is a feature that keeps working long after the reason for switching it on has quietly gone.
What makes this hard to see is that each individual instance still feels reasonable. Any single occurrence of the thing is fine, even pleasant. The cost is not in the occurrence, it is in the aggregate and in the shape it forces on everything around it: the evening that cannot be used, the trip that cannot be taken, the deeper work that never gets a run of clear days. Aggregate costs are invisible at the moment of paying them, which is why they accumulate unopposed.
The correction is to review recurrence itself, separately from any instance of it. Once or twice a year, look at the repeating entries and ask, for each, what would have to be true for you to agree to this today if it did not already exist. Some pass easily. Some fail immediately and have been failing for a long time. The point is not mass cancellation, which is neither kind nor necessary. It is that a commitment should be renewed at least once, deliberately, rather than simply never ending.