Getting a bunch of serving repetitions in a row in practice is good, but may not be the most game-like. In games, you might end up serving one ball then rotating and not serving again for another 10 minutes.
Western Washington University coach Diane Flick-Williams likes to mix up how her team works on serving by putting the players in pressure situations and giving them only one serve before moving to the next player. See how it works by watching the video!