That depends on the federation that the event is played under. In tournaments played under the International Tennis Federation rules, balls are changed after the first 9 games, then after the next 11 games, then after the next 9 games, then after the next 11 games, and so on. In ATP and WTA tournaments, balls are changed after the first 7 games and then every 9 games after that.
Tennis players use tennis balls during their match.
Tennis balls are changed during a match because when the can is opened the balls start losing pressure immediatly, reducing the bounce with each shot. This difference is not dramatic as tennis balls can be used over and over but professionals change balls so that they can get the most power and spin from their shots.
About 50,000 tennis balls in total. Matches (at least in the ATP) change balls after the 7th game of the match, then every 9 games after that.
For every tennis match there maybe 60 balls needed
New tennis balls are considered fresh and not "flat". Old tennis balls exposed to play and air become flat and do not perform normally in a match.
In a usual match pack of balls there are 4 balls, but you can get tins with 2- 4 balls in them.
for each match they give the match 500 balls in the huge buckets
no they have 4
Two players on each side compete in a tennis doubles match.
after every point
You change when the combined score of both opponents is an odd number. During a tie break, you change after both scores combine to 6 or multiples of 6.