To use Yandex personal services (Mail, Disk, and others), you must log in by:
When you log in through social networks or Yandex Elements you will be logged out after a few hours and your session will end when you close the browser. You will need to log in again after this time has elapsed.
If you have several Yandex accounts, you can switch between them without entering your username and password:
You can select an account in Passport and on other Yandex services that support this function. The selected account is considered the main one: from that one you will be logged in on services that you can't automatically switch between as of yet.
You can add up to 5 accounts to the list. To delete an account from the list, first switch to that account and then click Log out. That account will disappear from the list and you will automatically be logged in to the next one.
To remove several accounts, go to Add account and click Edit list.
If you entered your username and password on a given service, you only need to enter your password again if you haven't used Yandex services for three months. This is convenient if you're using your personal or home computer, but can be dangerous if you logged into a public computer (for example, in an internet-cafe).
The Public computer box lets you log in for a few hours only or until the browser is closed. Even if you forget to log out of your account, the public browser will not recognize that you ever logged in after a certain amount of time has elapsed.
To further protect yourself it's better to log out of your account: click on your portrait in the upper right corner and select Log out in the menu that appears. Several services have a Log out button in the upper right corner for this reason.
If you logged in on another computer and forgot to log out, go to the Log out of all computers link on the personal information page.
No matter how good your password is, someone can still look over your shoulder or steal it (such as with a virus). To protect yourself from this, you can allow one-time passwords.
You can learn more on how to use one-time passwords and two-factor authentication in the Two-factor authentication section.