There’s nothing worse than getting to a certain exciting point of your job search (the post-interview request for references, yes!) and scrambling to make sure you have a) solid references (and their permission), and b) accurate contact info for aforementioned solid references.
Being confident that your former supervisor only has good things to say about you isn’t enough. It’s both considerate and professional to ask to use someone as a reference—and important to let him or her know what you’ve been up to. Once you have your names lined up, check to make sure you have a current phone number and email address for each. Have this information at the ready so that if and when a hiring manager requests it, you have one less thing to worry about.