If you've ever deleted a Gmail contact and only later realized what a big mistake you've made, you can relax as long as you made the change in the last 30 days. Regardless of how many contacts you add or delete, Gmail keeps a 30-day history of every contact in your address book. So if you accidentally delete one or more, all it takes are a few clicks to bring them back.

The process makes for a somewhat blunt tool. You can't restore specific contacts, but you can retrieve every deleted contact back to a specified date. However, unless you've recently gone on a deleting spree, it shouldn't be terribly difficult to find the contact or contacts you're looking for.

This tip requires that you log into your Gmail account using a web browser -- not the Gmail mobile app. Any browser, whether you access it from your phone or laptop, will do. 

1. Open Google Contacts in your browser.

2. Tap or click on the Settings (gear) icon in the upper right corner.

3. Tap or click Undo changes.

4. Choose the timeframe you'd like to restore from, anywhere from 10 minutes to 30 days ago, then tap or click Undo.

5. Gmail will confirm by saying, "Your contacts list will be restored back to how it was on [date you chose]. It may take some time for these changes to show up on your device."

Still have a little remorse? Here are six ways to deal with regret, frustration and spam in your Gmail inbox. While you're tinkering, ratchet up the security on your Gmail account in just four steps. Finally, here are our favorite hidden Gmail features you need to know.