There is a lot of misunderstanding about passwords and password usage. I hope to clarify a few points about this.
The following is a list of some commonly hacked passwords:
The first one has been breached more than 23 million times to access sensitive information. All of the above passwords are in effect useless.
If you think of a password as a combination for a safe that keeps your online accounts private and secure it has to have a certain complexity to it.
It is not a case of IF a password can be cracked, but WHEN. Weak passwords take minutes to crack, but really good passwords take years to crack.
A password of 8 characters used to be recommended, but that changed to 10, although nowadays a minimum 12 is preferable.
The recommendation of using a combination of upper and lower-case letters, numbers and keyboard symbols such as @ # $ % ^ & * ( ) _ + is because you are then using the maximum variation of keys from the keyboard to create a password. The 47 available keys are doubled by using the shift key which enables you to use a combination derived from 94 keys. The permutations are increased massively compared to just using lower case letters or numbers.
The most common reason for a hacked email account is using a weak password.
When a hacker gains access to your email account they can then access every account connected to that email address. They can even lock you out of your email account and use it for their own needs.
Google recommends changing your password if your Gmail account is hacked, but hackers will usually put in a “backdoor”, so if you change your password, they will be aware of it. It is better to replace a hacked account with a new one. It is the same with “spammed-out accounts” you are better to get rid of them. Some spam is a nuisance but other types of spam are malicious.
Using one password for multiple accounts is a bad idea because if that password is cracked, the hacker can access all your accounts. There is a popular demand on the Dark Web for email addresses with a password, because there are so many people who use one password for everything.
You can check your password strength and get a better idea of good passwords by playing around with passwordmeter.com