I find it much easier to use than bookmarks. It's a great for research, when you have disparate bits of information spread out over dozens of sources. I close tabs as they become irrelevant. A window may have a lifetime of a few days to about a year. When I'm done I save its state using Tab Session Manager. By that time it's a 'best of' on that subject.

I also used 'New Tab Suspender' and 'Total Suspender' add-ons for a while in an attempt to reduce memory usage, but stopped due to Firefox crashes I assumed were caused by them.