Everybody has to make a judgement about how much value is delivered for the time spent. This will be different for different people. In my case, I find Twitter, Hacker News, Reddit and Facebook better value. YMMV.
I invested some time in G+ on the grounds that it might become so important that I had to be on it whether I liked it or not. It didn't. I can't see any sign that it ever will. Nor, it seems to me, can Google.
> One of the Chrome extensions i use
Is there a Chrome or other extension that will tell me how many of the people I follow haven't posted in (say) 3 months, without unfollowing them? Indeed, is there a guide to G+ add-ons and extensions? I've always found the lack of this type of thing a limiting factor, especially given the slow, crude and clunky nature of Circles in general....