If you delete Google Authenticator, you will no longer be able to use the app to generate two-factor authentication codes for your online accounts. ..
There’s more at risk if you lose your phone than just the password to your Google account — like all of the other Google services and apps you’ve added 2 factor authentication to using Google authenticator. These include:
Google Voice, Hangouts Dialer and Chat , Google Talk/Hangout SMS Backup , Google Play Games , Drive , Picasa Web Albums , Blogger , Google+ site, as well as a host of others. The point is that 2 factor auth is an essential protection mechanism for any online Google account. Google has published an article on What happens if I delete Google Authenticator? . (However, Google’s security literature has sometimes been shown to be incomplete or misleading)
Being able to easily recover your Google 2 factor authentication codes is a crucial safeguard for Google authenticator users who have mislaid their Google phone or lost access to it. Losing Google 2-step verification will leave all of the Google Apps and services you’ve enabled it for vulnerable to unauthorized access unless you can still log into your Gmail account from another device such as another computer with Google Chrome installed; which would allow you to use Google’s 30 day back-up recovery option as described in the aforementioned Google article. Most people don’t understand what they’re signing up for when Google 2 step verification is enabled — unaware that deleting Google authenticator from their phone could have serious implications.
Google Authenticator codes are only valid for a maximum of 30 days after being generated — so if you lose your Google phone; or switch to a new one before you’ve added Google 2 factor authentication codes to Google, there’s an easy way to recover your Google authenticator codes using the Google backup recovery codes that you set up when creating Google 2 factor authentication in the first place. This applies to any Google account you currently use with your Google Phone/Tablet and have set-up for Google Two Step verification, not just Gmail accounts.
