Ai: Recommended:
• Preferences (Windows)
• Settings (Mac)

Open the Preferences/Settings dialog box:

• Windows: At the bottom of the Edit menu select Preferences.
• MacOS: In the Illustrator menu that is at the top left of your screen (to the right of the Apple  icon), select Settings.
  

The Preference/Settings Categories & Settings To Use

• Units
  • Set all to Pixels (this is because almost all measurement
    
    
    
    
    
• File Saving
  • Disable (uncheck) "Automatically Save Cloud Documents Every:"
  • Default file location, select: "On your computer"