My calendar does not refresh often enough.

Open the macOS Calendar application.

If there is no calendar list on the left, select View Show Calendar List.

Right-click on the calendar and select Get Info.

In the Info dialog, select the interval period under Auto-refresh.

For most calendars, Every week is good. Some calendars, such as Weather, update more frequently. For these calendars Every day is good.

Do NOT select an interval more frequent than Every day. Calendars are not generated more often than that, so updating more frequently will serve no purpose.

Finally, click OK.