Authentication for everything

Go to your 'System settings...'(at the extreme right-hand corner of your screen and click on power icon to find it). Select 'User Accounts' and click 'Unlock' at the top right corner of the dialogue box and enter your password to unlock it and set the 'Automatic Login' to ON.Close and restart your system.

If that doesn't help, then do the following at terminal:

1. sudo visudo

2. look for this line admin ALL=(ALL) ALL (probably close to the last line).

3. replace it with admin ALL=(ALL) NOPASSWD: ALL.

4. Save and exit.

You should not have to enter a password every 2 seconds, but I understand the annoyance.

I personally do sys admin from a root shell

sudo -i

You can start graphical applications with gksu

gksu nautilus
gksu gedit /path/to/file/to/edit

The other feature that annoys people sometimes is gnome-keyring. Several solutions to that, including setting an empty password (for gnome key ring)

See : How to disable GNOME keyring?

If you must , you can configure sudo so that a password is not required, but understand the security implications if you choose to do so.

This is the classic link for additional information on sudo and additional options

RootSudo