Keeping Track of Domain Expirations?

phutureboy asks: "Between providing hosting for several dozen web sites and consulting for a number of clients who run their own servers, lately I find myself overwhelmed with keeping track of domain expirations. Although the domains which I've personally registered are consolidated under one Register.com account, there are many others spread among multiple registrars, to which I may or may not have administrative access. It would take days or weeks of frustration to audit them all and make sure my clients' contact information is up to date. Does anyone have any tips for dealing with this mess?"