The word "planet" comes from the Greek word for "wanderer" because to the naked eye the planets look like stars that move through the band of sky we call The Zodiac. Your personal horoscope is a 12 slice-of-life pizza-pie like map of how the planets lined up around you at the moment of your birth; it never changes, it represents your potential for self-actualization.
But the planets, wanderers that they are, don't stop for anyone and so your chart is like a snapshot hologram of the energies of the moment you were born and there go the planets, off on their merry way!
The faster moving planets, like the Moon, the Sun, Mercury and Venus, come back to the place they were on the day you were born at least once a year, the Moon goes over that place and ever place in your chart every month (the word "month" comes from the word Moon).
Astrologers call the return of a planet to the place it was when you were born a "transit" or a "return," as in "Many happy returns - of the Sun - when you have a birthday."
Mars takes over six hundred days to come back to that place. Jupiter takes twelve years, Saturn takes 28 years and Uranus takes 80 years - all these time periods are approximate, give or take a couple of years.
Neptune and Pluto take too long to circle the solar system so until science get's off its collective ass and re-discovers how to help us live healthy and strong to the age of Methuselah in the bible, about 400 years, no one is going to have a Neptune Return or a Pluto Transit from Pluto.
The return of any planet is an important occurrence but the return of Jupiter, the jovial planet of growth, every 12 years brings a new cycle of growth, usually accompanied by good fortune.
The return of Saturn, the stern teacher of the realities of time, occurring every 28 years marks the passage of youth to adult, then adult to sage at 56, and sage to wise elder at 84.
The return of the planet Uranus is all about making your life a statement of your originality, which is why it is the planet associated with Astrology, itself. As I said, Uranus takes about 80 years to come back to the exact spot it was on at the moment of your birth but if you want to know what that means then you should learn about what happens when we hit 40, approximately, and Uranus is exactly opposite the place it was on the moment we were born - The Midlife Crisis!
Yes, you can predict when a person is going to either consolidate and perfect their ability to enjoy their life as a statement of the unique individuality OR buy a midlife crisis red sports car, leave their job, break up their marriage, and upset everyone around them. Like clockwork, the clockwork of the planets, the Uranus opposition times the point of no return for each of us and our efforts to be ourselves fully.
The way all the planets work in astrology, or at least the way I have come to think of them, is simple (hah!): If you are in harmony with yourself and the cycles of your life, the planet doing the transit, return or angle to the planet(s) of your chart will help you do so, as symbolized by that planet's energies and the signs involved.
If, however, you resist doing the work of changing and adjusting to the new realities of your life and the need for you to meet the demands of becoming yourself fully, then watch out! The planets involved will still help you, but you won't like it one bit. They'll help you with a quick kick in your ass in some way, some kind of jolt that they craft in perfect planetary deviousness. They're like the family, friend or co-worker that was "only trying to help" but whose actions really screwed you royally.
If you want a personal astrology reading, I offer different options here.
(artwork by Amy Zerner)