':return: True if movie details are considered to be expired, ie. need of update'

@property
def expired(self):

    if (self.updated_at is None):
        log.debug(u'updated_at    is    None:    %s', self)
        return True
    refresh_interval = 2
    if self.year:
        age = max((datetime.now().year - self.year), 0)
        refresh_interval += (age * 5)
        log.debug(u'movie    `%s`    age    %i    expires    in    %i    days', self.title, age, refresh_interval)
    return (self.cached_at < (datetime.now() - timedelta(days=refresh_interval)))
