My approach to this has been to retreat to books whenever I find myself too immersed into any digital activity that doesn't yield any tangible results at the end of it (i.e. it's just a time filler). Books can be very engaging, to the point of "one more page" syndrome - but they're still finite, and much easier to put away, all in all. Plus, it is very rare to find a book that doesn't have even the smallest nugget of genuine contribution to one's experience and knowledge. And there's so many good books, you could fill many lifetimes with them.