Saturn doesn't make things easy. That's the role of the taskmaster of the zodiac. Saturn commands us to get to work and to work hard. Discipline and responsibility are important to this planet, yet if we're eager to conquer the world, that's okay, too.
Much like Father Time, Saturn implores us to look at the clock (its glyph, after all, is the sickle of Chronos, the God of Time). Is there time for everything we want to do, or are there limits? Those limitations are important to Saturn, and we must learn to manage them. Restrictions are the province of this planet, as is any form of discipline or delay.
In keeping with the passage of time, Saturn governs old age along with the lessons it teaches us. Learning life's lessons is key to this planet, in keeping with its role as teacher. The majesty of older age also brings with it a certain sense of tradition, conventionality (our learned patterns of behavior) and wisdom, and Saturn is mindful of these characteristics. This planet applauds our perseverance and the fact that we've withstood the test of time (yes, time comes up once again). This senior status further brings with it a measure of authority, and Saturn lords over that as well.
Structure, order and the way in which we conduct our affairs are all ruled by this ringed planet. Contraction and the reining in of assets are also important here. Lastly, Saturn, again in its role as teacher, concerns itself with karma and the lessons which past experiences might bring.
It takes Saturn 28-30 years to complete its orbit of the zodiac. It is masculine energy and rules both Capricorn and Aquarius, and the Tenth and Eleventh Houses.