There isn't any option in cPanel that I know of which does this. There may be a plugin but doubt it. Your best bet is to use Google Calendar and install the plugin into Chrome you can setup multiple notifications pop-up, and email as well as set it to notify you any quantity of days in advance. If you use Android your phones calendar can sync to Google so you'll be notified on your phone, email, and in your browser
** Update **
http://forums.cpanel.net/f5/whm-admin-email-notification-customers-approaching-expiry-214751.html#post887742
Accounts created on cPanel/WHM do not expire, so there are no native
options available that will alert you of an approaching expiry. This
should be handled by a billing application. If you are looking for a
billing application that integrates with cPanel/WHM, you can find a
list at:
Application Catalog
There are several listed under "Billing Automation", so you may be
able to find one that offers a more simple approach to meet your
needs.
Thank you.