Here's a simple thing that has helped me avoid the issue (which otherwise is quite nagging): Starting from the HN main page, I first open the discussion pages

Here's a simple thing that has helped me avoid the issue (which otherwise is quite nagging): Starting from the HN main page, I first open the discussion pages of all the stories I potentially want to read in new tabs (till I start encountering older stories that I have already gone through). This process is fast enough to not encounter expired links. For each story now, I click the link leading to the story from the HN discussion page, and get back to the discussion page simply using the back button. When done, I simply close the tab.