ok, two reasons for Bon Jovi to have support bands....

a) Like letitrock said, it breaks up the time a bit
b) young bands need the chance to play for an audiance, if you don't have support bands, people will never get the chance to progress...

Ok, so Bon Jovi have made a shambles of point b. They choose bands like Ronan Keeting.... he's playigna 20000 arenal in Manchester, does he really need a break? ALso, the band don't seem to choose the bands themselves, I think they should be trying to give this break to somebody who deserves it, as opposed to just helping the record company's plug bands. It's bands like bon Jovi who are responsable for the crap music out there now, there are young bands, it just takes bands like Bon Jovi to give them the chance to stand in front of peopel and get heard.