If you want to follow some specific threads, I suggest you try the "Notify" function button at the top of any topic/thread. If you post in a thread or have read a thread, you can activate the notify function after, and you then will receive a notification by e-mail for the next new reply after your post/your reading.
In the e-mail, there will be a direct link to this reply, so no energy lost for searching. To my knowledge, you will not receive any further notifications until you visit the thread again, even if there are other replies ( anyway, in the e-mail title, you see what topic is referred too, so no big deal to go to the oldest notification).
That is the best alternative solution I can suggest for the fact that the "Unread Posts" function do not lead you to the last unread reply by you of a thread ( Like some other forums do)
You can unnotify to any topic by using the same button at the top.
This "Notify" function can be customized further in your member profile options, see at
https://wiki.simplemachines.org/smf/Notifications
