Do not pursue what is illusory - property and position all that is gained at the expense of your nerves decade after decade and can be confiscated in one fell night. Live with a steady superiority over life - don't be afraid of misfortune, and do not yearn after happiness it is after all, all the same the bitter doesn't last forever, and the sweet never fills the cup to overflowing.
Happiness is equilibrium. Shift your weight. Equilibrium is pragmatic. You have to get everything into proportion. You compensate, rebalance yourself so that you maintain your angle to the world. When the world shifts, you shift.
I guess what I'm trying to say is, I don't think you can measure life in terms of years. I think longevity doesn't necessarily have anything to do with happiness. I mean happiness comes from facing challenges and going out on a limb and taking risks. If you're not willing to take a risk for something you really care about, you might as well be dead.