How many apps can one have on a phone? Or how many would one want to have? Each app would keep running its background processes and such; keep draining batter

How many apps can one have on a phone? Or how many would one want to have? Each app would keep running its background processes and such; keep draining battery. Maybe people don't bother checking what permissions does an app want; from reading your contacts to stuff on the SD card. Nonetheless, it's intriguing to see that people still see room for new social networks.