i think maybe at the bigger events they use more, all weekend at this challenger it was 4. i guess it saves costs, you can get by on 4 after all, esp with ball kids.

one thing that annoyed me was that at the matches they had an umpire and 3 line judges, 2 of which were calling the tramlines and one checking the serve line. all well and good when play was outside and on there were 6 courts in use plus chalk flying up off the lines, but for the matches indoors they kept the same line judge setup, even though they were playing only 2 courts, so you still had the 3 judges with none on the baseline leaving up to the umpire. it's obviously much harder to call a baseline on indoor hard as the ball is flying through and there is no chalk to help (and i saw quite a lot of bad calls on this myself), so what i don't get is why have so many judges spare, they had enough for 6 courts + rotation so there must have been loads hanging around when play was only on 2 courts, why not use them to cover the baselines?