Os Guinness argues that God can use and has used people in their youth, but God also has accomplished some of his best work through people more advanced in life experience:

It is said that gymnasts are old at twenty, boxers at thirty-five, cricketers and baseball players at forty. Yet doctoral students are old at thirty, while young as professors at thirty-one. Novelists, we are told, do their best work in their twenties and thirties, whereas painters are still young in their forties. Most leaders of the great revivals and awakenings were under the age of thirty, but many of the greatest leaders of nations have been in their eighties. Golda Meir only became prime minister of Israel at the age of eighty.

In short, the way of excellence as well as contentment is to be "our utmost for God's highest" at whatever age we are. Another truth we tend to forget is that many things in life are better with age. The foolishness of the 1960s slogan, "Don't trust anyone over thirty," was upended by Thomas Oden's brilliant quip, "Don't trust anyone under three hundred." When Andras Schaff, the virtuoso Hungarian pianist, played a sixtieth birthday concert in London, he chose to perform Beethoven's "Diabelli Variations." He had waited until he was fifty, he said, to play Beethoven's thirty-two sonatas. And only after he had performed twenty complete cycles of the sonatas would he dare to move on to the "Diabelli Variations." "It's the most wonderful, the most colorful composition Beethoven ever wrote … . I cannot understand pianists who are 20 years old and they immediately play that piece. It cannot be serious." Another pianist, Artur Schnabel, remarked similarly, "Mozart sonatas are 'too easy for children, and too difficult for adults.'"