(Or, How I love 1Password and even bought one of their really geeky tshirts)
Scene: Last night
Newly restored iPhone: Put in your voicemail password!
Me: Uhhhhhhhhhhh (try a few random 4-digit combos)
Me: UHHHHHHHHHHHHH I DO NOT KNOW
Me: Maybe I put this in 1Password?
1Password: Here is your voicemail pin!