Re: few days?
But even then you have to get hold of the passwd file to do even that.
In this century you would need the shadow password file which requires root access, and, a rainbow file would not help as a random “salt” is added to the password before encryption.
The biggest problem is complex password rules which demand a mixture of lower and upper case plus a number and a special character, which requires a post it note to remember.
A minimum of 12 any character you choose would provide better security.