Roger Federer shouldn't look this good.

He has played 959 professional matches in his career, appeared in 46 consecutive Grand Slam tournaments and spent more than a decade criss-crossing time zones while collecting a record 16 major singles titles and more than $60 million in prize money. Married and the father of twin 22-month-old girls, Mr. Federer brings his family—jet lag, runny noses and all—on the road with him from Melbourne to Paris to London to New York, and many places in between.

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