Why does Gmail frequently ask for my password? It rarely did this until I changed my password.
- Your browser is dropping the login cookie, perhaps because of a browser bug, or you cleared cookies, or you were using an incognito window and closed it.
- You have more than one Google login, and Google's "multi-login" doesn't work out very well. The best solution is to use a separate Chrome profile for each login. See Force Google+ to login using correct user
- Perhaps this browser has an old Google login cookie, so Google asks for the new password, but something is blocking it from saving the new cookie. You could try clearing the Google cookies. Also try temporarily disabling most browser extensions.
- Perhaps there's a Google account security setting for how frequently it asks for a password, but that's news to me.
I have found that I get prompted when it loses connection between me and the server. Other times, it has gotten stale (been online for too long). Having multiple services that use your Google account can also cause you to be forcibly logged back in. I don't have supporting documentation for any of these. This has just been my experience.