Tennis players rarely break strings anymore, but they still want their rackets to be given a fresh set.

"The 4:30 wakeup to start stringing tennis rackets is not the most pleasurable thing in the world," Yu said. The rackets Yu strings will be used in about six or seven hours, when the strings start ...

But for fun, he found his way onto the city’s tennis courts. The sport could be expensive, he learned, especially in New York, so he eventually bought a tennis racket stringing machine to save ...