The most recent XKCD comic (full image below) points out one of the dangers of password reuse.
If a person uses one common password whenever they set up a new account on a website, they make it easy for a shady individual to use a new site or service to mine user’s information for usernames and passwords to more important websites like bank websites.
I practice a medium level of security - I have a typical password that I use when I log into a site that I really don’t care too much about, but if I have a website that I want to be secure, I use a unique password that I don’t employ anywhere else.
To make my life easier, I use a password manager that stores these unique passwords. It is accessed by its own unique password that is the most complex one I use. I also carry the database for this manager on a USB drive and my Android phone so that if I need to access anything while I’m not at home I can access the passwords securely.
So gentle readers pay attention to your use of common passwords and their risks.