Do you prefer forums which auto-unflag older threads?

…like the SD, or do you prefer forums where every thread remains marked unread until you actually read it? The downside of the Dope’s method is that the flag can and often does reset halfway through your visit; the downside of the no-auto-unflags is that you have to hit this button (usually at the bottom of the main forum page) to unflag them all manually. In an ideal world, the flag wouldn’t move until you’ve been logged out of the forum for at least 1/2 an hour. I’ll provisionally throw in my preference for the SD’s way, despite the bugs, because it’s annoying for me to have to remember to unflag them myself.