Update - 15 April 2019:  The PwnedList site now appears to be offline.  In it's place you can try the "Have I Been Pwned" site at https://haveibeenpwned.com/

While the "Have I Been Pwned" site suggests using 1Password for your password management, there is more than one way to accomplish this.  What's important is that you use strong credentials that are unique on each site.  That way if your credentials are compromised on one site, it only affects that one site.

Given that 8 character passwords are no longer considered secure, you can likely improve your security with the use of pass phrases and 2-Factor authentication. 

Here's a pass phrase generator that looks promising: https://www.useapassphrase.com/ and the site provides some good information on why a pass phrase may make more sense for your.

For 2FA, the Google Authenticator has been quite popular, but for people with mulitple devices, Authy is worth looking at too.

Below is the old information from this post.

"Have your accounts been compromised? Find out.

PwnedList is a tool that allows an average person to check if their accounts have been compromised. No passwords are stored in our database. ..."

The above text is from https://pwnedlist.com/ . This site is designed to be secure means of easily checking to see if your username or e-mail address is know to be compromised. You can even test your username or e-mail address without sharing them with the PwnedList web site. As shown on https://pwnedlist.com/learn you can hash your username or e-mail address with SHA-512 first and use the results to perform the lookup.

Another good recomendation provided on the site is in their Password tips.  The use of good password manager application can make the task of managing multiple credentials much easier and safer.

If you have any questions, please don't hesitate to contact me.

-Bob