On a Archive: how could I break cache for the current year, but not the others?
You could use the new Cold Cache pluging from P&amp;T which:


  Adds a new {% coldcache %} tag to Craft, which works just like Craft’s
  built-in {% cache %} tag, except that this tag won’t record which
  elements and element queries are active between its tags. The only way
  caches will ever get deleted is if they expire, or an admin clears
  them using the Clear Caches tool in Settings.