Just recently, someone I know told me that a technician at a tech company that shall remain nameless accidentally deleted his 400+ contacts. Not cool. How does something like that happen?!? Anyway, that was the impetus for this post.
If you're a Gmail user, all of your contacts are stored in Google Contacts (https://google.com/contacts). If you should happen to delete accidentally one or more (or all) of your contacts, do not freak out! Simply follow these steps:
1. Go to https://google.com/contacts (or https://contacts.google.com). You can also get there from Gmail by clicking "Gmail" in the top left corner of the page (beneath the Google logo) and choosing contacts.
2. Locate and click the "More" menu. This menu looks a little different depending on whether or not you're using Enterprise Gmail.

Regular Gmail Interface

Example of an Enterprise Gmail Interface
3. Choose "Restore contacts."
4. On the window that displays, choose a pre-defined date/time to which to restore, or enter a custom date time as the restore point (please note that you can only restore to previous points in the last 30 days).
5. Click "Restore."