Gmail's sign in page offers the checkbox "stay signed in". Does this mean that it will stay signed in indefinitely? If not, then for how long?
The "need help?" link is not immediately helpful.
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Sign up to join this communityNothing lasts forever. You stay signed in as long you don't clear your browser cookies or manually sign out. If you use any third party junk cleaner tools like CCleaner to clear browser cookies, that will get you signed out as well.
Gmail's session cookies have a relatively long expiration date as you can see here:
This is discussed in Google's official blog where they've mentioned the following:
In the coming months, Google will start issuing our users cookies that will be set to auto-expire after 2 years, while auto-renewing the cookies of active users during this time period.
It means that if you close that tab/window and then open gmail again after sometime*, you will NOT need to log in again.
*sometime refers to amount of time your log in is valid - typically couple of month in case of gmail.
Note 1: If you clear your browser cookies, directly or indirectly, you will be logged out.
Note 2: This will be a security risk if this is not "your" machine (e.g. Hotel) b/c, if you do not sign out at the end and just close the window, the next person who opens gmail will be able to access your email.