Well sysyems get hacked etc, but if you accidentally log in to something with a MASTER key, you are open to problems. ie use your POSTING key on a daily basis

You should have ALREADY saved your PASSWORD that was used to generate your keys
Next go to Profile >Wallet > Permissions and copy paste all FIVE keys to a safe place.
(eg a text file on a memory stick)
The “OWNER” key is the ‘master key’, keep it VERY safe
Daily logins for posting should use your Private POSTING key.
Once you have copies saved, log out and log back in with USERNAME & your POSTING key
Hope that helps some.
$0.02