As a general rule, any password you create should be unique and not re-used across sites.
Doing this prevents people getting access to your accounts on other sites using a common password.

It can be hard to keep track of all your passwords, there are several options for making that task easier. One of the best is possibly 1Password, a browser based password manager. For a small monthly charge it makes your passwords available on all your devices.
As a last resort, use the password manager in your browser to save your passwords.

Passwords for accounts on our site have a certain set of requirements:

They should be at least 12 characters long,
Contain upper and lower case letters, digits and at least one special character (e.g. $, !, %)
Not contain words or repeating sets of characters, e.g. abcd, 1234

In an attempt to stop password re-use, we also do not allow passwords that have previously appeared in data breaches. To do this we use a service provided by Troy Hunt, this same service is used by many other organisations, not the least of which is UK Government and 1Password.