Details emerging of another email breach - three quarters of a billion addresses possibly compromised. You can check by entering your email at https://haveibeenpwned.com - all this site asks you for is the email address, it doesn't ask for any passwords/personal info etc, and it will let you know if that address is at risk. If it flags it as compromised then you probably want to change your password.
Edit: also, if you use the same password for other sites (tut tut, wags finger) then you probably want to change those too because a common form of attack is to use your email + password combination for logging into other sites.