system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:why do orchestras need music sheets but rock bands don't?

Don't they practice? is the conductor really necessary?
gpt
In addition to other answers, rock bands play the same songs over and over, most orchestras don’t.  They might play the same pieces for a few performances one but then their next performances will be a different set of pieces probably by a different composer.  Looks up any major symphony orchestra schedule and you’ll see how many different pieces they play in just one month!  It’s entirely different styles of performance basically with different goals and different needs.