What Max(IT) said: folders, folders, folders. iOS and Mac.
As for iOS devices, home screens have the most used apps, the REALLY most used reside on their own on the screen, others in folders. Screen not completely filled (eg. so can drag an app that will be heavily used for a short time span onto home screen). Phone, Messages, Mail, Safari on launch bar.
Then comes more prioritizing and foldering. Secondary apps on next screen, games on third, fourth screen some apps that MIGHT be useful once or twice a year but should probably be deleted since probably been a LOOOONG time since used, "app ghetto" on fifth screen.