Hi mistertropical, there actually is an important difference that you can't really tell from the wording.

In the Cookies section, the checkbox has the effect of changing what Firefox does when a site requests Firefox to set a persistent cookie (distant expiration date). If the checkbox is checked, Firefox will instead set a session cookie that expires when you close Firefox, unless you have created an exception allowing the site to set persistent cookies (using the Manage Permissions button).

In the History section, with the details expanded (Firefox will: Use custom settings for history), the "Clear history when Firefox closes" feature doesn't respect any exceptions, and clears all persistent cookies -- assuming Cookies is selected as one of the categories when you click the Settings button over the right. If you want fine control over cookies, do not use this feature to clear them.

Note that Site Preferences refers to your preferences for the site, such as your custom permissions for cookies, popups, etc., and your preferred zoom level.

As for the more general question of recommendations, I use the checkbox for session-only cookies and make exceptions as needed (i.e., when I get annoyed with logging in again). That's it; keeping that part simple. I run the NoScript extension, which is a job in itself, to manage scripts in pages. I'm sure others have their own approach.

Thanks for the reply, it's been helpful. But -

Is there a difference between setting non-persistent cookies (under Cookies) and clearing cookies (under History)? Seems that these two options have the same effect?

Also, does having Site Preferences clear Custom Permissions for Cookies seem problematic? I would think separating those options would be preferred, or at least more clearly defined.

mistertropical said

Is there a difference between setting non-persistent cookies (under Cookies) and clearing cookies (under History)? Seems that these two options have the same effect?

They have the same effect, unless there is an exception set for a site.

Also, does having Site Preferences clear Custom Permissions for Cookies seem problematic? I would think separating those options would be preferred, or at least more clearly defined.

I don't understand your question. ?? The reason you are able to clear Site Preferences under the "Clear history when Firefox closes" feature is that they could disclose some history. For example, if you visited a site and customized the zoom level or saved a popup permission, then someone could, by poking around in data files, find out you visited the site based on those traces. (A cleaner approach is simply to use a private window when you are going to go to a site you don't want recorded anywhere in your Firefox data.)

Note that under "Options/Preferences -> Privacy & Security -> History" there are two ways to clear the history. The first is "Clear Recent History" (Ctrl+Shift+Delete; time range possible) and a second under "Clear history when Firefox closes". Using either of these to clear cookies will clear all the cookies, regardless whether an allow exception was created or not. Only "Delete cookies and site data when Firefox is closed" will allow to keep cookies with an Allow exception. If you use "Clear history when Firefox closes" to clear the browsing history then you won't be able to reopen tabs on the next start (Restore Previous Session).