Firefox isn't with useful tool, which is tabs suspender, it saves of much hardware consume and doesn't allow your PC stay slowness and/or your own internet, because tabs can consume internet and recourses in background without you use it, so that's important and should be in all popular browsers including Firefox. I recommend they base on auto tab discard and possibly performance tool (by Microsoft Edge), because auto tab discard extension is really complete and very useful, mainly it saves where you stop on certain time video and performance tool saves much your recourses on your computer and is very efficient: