Imagine that you chose your password to be a number comprising 44 bits, each 1 or 0. How long would it take a computer to discover your password (with certainty) if it made 1000 guesses/second?
It needs to try all 2^44 possible numbers, and at the rate of 1000/sec this will take xxxx seconds, which you can convert to minutes, day, years, and it comes to 557.8 years before all possible 44-bit combinations of bits have been tried. Statistically, there is a good chance of hitting the password in half this time.
