Once they've relisted three times they just drop into unsold. 

If you keep the emails from when you first listed them you can work out how many times they've relisted, but there's also a way to tell whether they're on their last cycle.  If you look on the drop down menu to the right of the listing (in your selling list), if one of the options is "remove auto relist" it means they'll relist at least once more.  If that isn't one of the options then they're on their last cycle and will drop into unsold when they end. 

If you don't want them to automatically relist (eg. if you want them to relist twice but then you're going away), just click on remove auto relist for each item.

If you remove auto relist but decide you want to put it back on, you'll need to do it by editing and ticking the box - before it ends, of course.