I've come to think of my life as having been lived in thirds. The first third was my childhood, adolescence and completing my education. The next third was developing my professional identity, marrying, and having and raising my two children, a task never done but ever changing. Now that my first child has left for college and my younger child is looking at colleges, I find myself wondering how I want to live the last third of my life.

It seems that life is lived ever less spontaneously as we age. The first third is full of surprises and mistakes, changes and learning. The next third requires a little more planning. Change careers? Marry and remarry? Have children? When? How many? And eventually decisions seem to be interwoven with the needs of the family and, so, less spontaneous.

Now, in the approaching last third of my life, do I plan it or do I return to the state of spontaneity of my youth or something in between. I have learned that I enjoy living life in a warm climate. That would require a change of residence. I am no longer willing to read any book and will abandon one that doesn't rope me in by the first night's reading. I am less worried about what people think of me, so more willing to give my opinion. And there is grieving of course: the death of my father, the decline of my mother to dementia, watching my children leave the nest with more and more ease with each subsequent foray. But there is also a sense of freedom and a sense of possibility.

When I was young I thought that once you reached adulthood, the rapidity of changes slowed down. It doesn't. Everything keeps changing. The physical changes are the most obvious, of course. But the sense of a finite future is the hardest thing to accept. I still haven't decided if the best course is to ignore that fact or incorporate it into my final third. It could be freeing or it could be terrifying.

Well, I have about 18 months until my daughter takes her first flight out of the nest. Most people hope their children are ready. I know mine are. I just hope I'm ready to leave the nest myself, to live the last third as fully as possibe.