I am now so exicted that this extension acutally works!! Cannot believe it! I don't know anyone out there is like me always have over 50+tabs opened. You said that is what bookmarks for? Nope. Let me tell you, if you put into the bookmarks you will just forget it. If I keep them opened, I will notice them, and never forget what I left whether or not need to continue or finisht it. Before using the extension, my Firefox always ate up 16+GB memory, I needed to upgrade my PC memory to 32GB, as I am also a programmer working with different platforms that use heaps of memory. After I install this extension, my Firefox only uses 1.6GB, 10 times less, I am not joking. Cannot be happier to find the extension. The only thing that can be improved is if there are more explanations on each option would have been better. I don't know why Firefox team cannot do it...after so many years...