depends on the content you stream, more movement = more bitrate. E.g. streaming a still image can be done with nearly no bitrate at all, quake 3 can take up to 20 mbit/s to get a usable video depending on the encoder.
See the Twitch broadcasting guidelines. This is also best practice with all streaming services.
and Youtube:Twitch Streamers - Twitch Video Encoding/Bitrates/And Stuff
stream.twitch.tv
Choose live encoder settings, bitrates, and resolutions - YouTube Help
Choose a quality that will result in a reliable stream based on your internet connection. Read this article to learn how.support.google.com
ps. improve your Google search skills.
No, this is their recommendations for their streaming service, they are not best practices and especially not for ALL streaming services. This recommendations are for most other streaming services pretty much trash.See the Twitch broadcasting guidelines. This is also best practice with all streaming services.