And, if the location is otherwise suitable, generally have a jolly good (party) time.
Don't tell the 'beancounters'
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A friend of mine used to fly for a major charter airline in Europe. Sometimes they were indeed so lucky, as to have a week off at one of the sunny destinations in the Caribbean. On other occasions the crew was just sent 'dead-head' with a local carrier to the next island, to fly the return trip of a different rotation - so they just had about 24h off.
Concerning that Lufthansa flight to a certain destination once a week - as far as I know the airplane sits on the tarmac while the crew is on minimum rest at the destination, thereafter they do the flight back to Frankfurt. So no week-long layover for them.