Tennis rules govern court dimensions, scoring, equipment specs, and play standards across matches, sanctioned tournaments, and casual games with tested explanations.
The advice you have probably heard goes like this: if the ball clips the net on a serve and still lands in, you call "let" and serve again. Clean, tidy, done.
Watch a busy public court for an hour and you will see dozens of serves that break the same rule. Almost none get called.
There is a tidy idea that gets repeated on coaching blogs and in pub conversation: a tennis court is just a rectangle, 78 feet by 36, with a net down the middle.
A father sat next to me at a 12-and-under tournament last spring, leaned over, and asked what "thirty-fifteen" meant. His daughter was serving. The scoreboard had just flipped.