At each seven-year interval, Mr. Apted must decide how to edit all his past material in order to show us how his characters got to the point at which they now find themselves.
In 1558, the first ecclesiastical Visitation since the Reformation's introduction was undertaken, while others were now undertaken at seven-year intervals thereafter.
Only later did its immense popularity give us the idea to go back at seven-year intervals.
Also, it's a seven-year interval between killings.
The series' ambitious time-lapse method, whereby subjects are revisited at regular seven-year intervals, makes possible an astonishingly intensive view of their lives and evolution.
Joint exercises of the Ukrainian Navy and the Russian Black Sea Fleet where resumed after a seven-year interval in 2010.
It tracked their lives at seven-year intervals to discover whether their hopes and aspirations had been achieved.
We had thought of rotating the population in groups at seven-year intervals, but, to be fair, we would have to take the oldest men and women still able to benefit by the radiation.
ENSO conditions have occurred at two- to seven-year intervals for at least the past 300 years, but most of them have been weak.
In a parody of the film "35 Up," three very different lives are checked by a television producer at seven-year intervals.