I think it matters on if your are the headliner or not. If you are the headliner I would consider 90 minutes a standard if you have at least 2-3 albums. 45 Minutes if you are a "mega-rapper" with only 1 album but headlining. Which means you had some "meaty" undercards to satisfy the crowd.

The crowd has alot to do with it too. If it's just "one of them shows" where all the stars are aligned. I wouldn't be madd if you went 2 hours. After that a nigga like me ready to go to bed..LOL. I can't party like that no mo'.