I used to do the "Last 50 Posts" thing. No longer.
Instead, I go to the Forum Index, and look at the most recent post date for each forum in which I might be interested. If the date is after whenever I last looked, I open the forum, which shows the threads in order of most recent post. I only open threads of interest to me, that have last-post dates for after I last looked. Inside the thread, "new" posts are indicated, which helps me zero in. This approach avoids the difficulty of identifying threads when the post "Subject" lines shown in "Last 50 Posts" are different from the original thread "Subject."
This eliminates most of the frustration I used to feel in toggling in and out of posts only to end up in threads I've already read or that have gone in uninteresting directions.