The idea of this extension is fantastic! I have it installed since years (it is an older laptop, where RAM is precious) and can see the immense effect of putting the tabs to sleep.
There is still a key point missing to make it consistently powerful: The counter should be applied for each individual tab: When I have e.g. 15 tabs open, 12 may go to sleep, but I am still actively working with 3. But these 3 tabs then have to wake up every time I switch between them - which costs time on machines with little power.

Very nice idea. But wish for 2 extra features:
(1) White list. Right now we can only choose to ignore all pin tabs or not. For example, I only want to ignore gmail pin. So a white list will be more flexable.
(2) This is more for desktop and I switch between a lot of tabs. However tabs reload the whole page when activating. This become quite painful. It will be nice to have option to choose the "sleep mode" between suspended(eg. just stop/pause script) and clearing completely(the current way).

This addon is really useful for people like me who open a lot of tabs. it really does reduce ram usage.

However there seem to be some issues still lingering:

1. For some reason opening a new tab from either a hyperlink/image/etc... through right-click/scroll-button, will make the new opened tab, completely blank. the name of the tab is still there, but the page cannot be accessed and since the url is also blank, you pretty much can't do anything. This is really annoying and needs to be looked at

2. there are times when my browser is stuck and i can't do anything. The best example i can give is when i turn off the addon while a bunch of tabs are open.
This needs to be adressed as well

3. Could i get more explanation on the whole pinned tabs? how do i do that?