Know which folders sync
A service may synchronize only selected folders or app data.
Deletion can sync too
Removing a synchronized file on one device may remove it elsewhere, depending on the service.
Account access matters
Strong account security and recovery information are part of protecting cloud-stored files.
Keep independent copies for important data
Critical files can justify more than one storage location or backup method.
General consumer technology information only. Interfaces and menu names change. Before resets, reinstalls, storage changes or other major actions, verify that important data is backed up and use current manufacturer/service-provider instructions.