When it comes to passwords, size does matter:
The best passwords have mixed case letters, numbers, and special characters
Total number of combinations = (number of characters in your character set) raised to the number of characters in your password
How long would it take a hacker to guess your password that included all of these if he could guess 100 billion passwords a second?
1. 8 characters (96**8 combinations) - 20 hours
2. 12 characters (96**12 combinations) - 194,288 years
3. 15 characters (96**15 combinations) - 171,894,463,426 years (172 billion years - that's over 10 times the age of the universe)
4. 18 characters - 152,081,219,993,855,034 years (152 quadrillion years - by this time, all the matter in the universe will have decayed into elementary particles)
change your passwords periodically and use strong passwords (passwords based on random character sequences)...
use two factor authentication when possible
don't set up email servers in your broom closet
Not even the Russians will be able to hack you