I register unique email address for every site / company I use. It goes to a catch-all account but as examples I have used tesco@{domain}.com, amazon@{domain}.com, apple@{domain}.com etc..
That way I:
a) Know where my data has been leaked, and by whom
b) Can blackhole that address so it isn't used in the future and my mailbox doesn't get full of chaff.
Some of the worst offenders, responsible for my receiving the highest number of phishing emails have been: LinkedIn, LastFM, Tumblr, and, MyFitnessPal. Just something to bear in mind.