The seven year periods are quite pronounced in my life; I can see that in the way my Venus is not much aspected except by Saturn.
It's not the same for everyone. Some are more governed by Jupiter's 12 year cycle, some by Mars's 2 year cycle, but everyone has all of the planetary cycles operating all the time. Interacting with each other - re-inforcing or moderating - at different times.

Reason. In Astrology.
Encountering Astrology produced a shift in my perception. I could no longer look at the rational, scientific paradigm with quite the same force of belief as I used to.
I couldn't look at history in the same way either.