I realised just this past week that this tiny activity is often overlooked, meanwhile it could have a negative impact on one’s account security.
To check now, simply click this: https://myaccount.google.com/permissions – this takes you straight to the applications page that have one access or the other to your google mail/account. If you see any application you don’t need or have not used in a long time.
Click on it to reveal the ‘remove access’ option. Click on ‘remove access to proceed’.
P.S: If you have other frequently used online services like twitter, zapier, facebook, etc? Go review the apps you gave permission to now. That option can usually be found under settings, applications/security/permissions.
P.P.S: To learn about the risks to your google account, click here.