Retiring NYT columnist William Safire, 75, offers some sage advice -- don't retire. Change.

An excerpt:

Here's why I'm outta here: In an interview 50 years before, the aging adman Bruce Barton told me something like Watson's advice about the need to keep trying something new, which I punched up into "When you're through changing, you're through." He gladly adopted the aphorism, which I've been attributing to him ever since.

Combine those two bits of counsel - never retire, but plan to change your career to keep your synapses snapping - and you can see the path I'm now taking. Readers, too, may want to think about a longevity strategy.

We're all living longer. In the past century, life expectancy for Americans has risen from 47 to 77. With cures for cancer, heart disease and stroke on the way, with genetic engineering, stem cell regeneration and organ transplants a certainty, the boomer generation will be averting illness, patching itself up and pushing well past the biblical limits of "threescore and ten."

But to what purpose? If the body sticks around while the brain wanders off, a longer lifetime becomes a burden on self and society. Extending the life of the body gains most meaning when we preserve the life of the mind.

Actually, the Times ran a quartette of Safire columns. Here's the other three:

1. How to read a column

2. Win some, lose some

3. First lady follies