For me , the bits of paper saying that I am BA this or Phd that, meant little to me, except in the fact that it was a personal goal I had set for myself, it was my challenge to me. For me, at least, a life without purpose (whether it be in education, research, parenting, cooking etc) is a wasted life. I now work in an industry that doesn't require my scientific knowledge, but that does not mean it was wasted time or effort in gaining that knowledge. I have lost nothing, and I am constantly amazed at how useful this knowledge is in every aspect of my current life.
It doesn't matter whether the learning comes from books, nature, even our own children, its the 'learning' that matters. I was questioned by one of my Science lecturers about why I chose to study philosophy units, while studying for my chemistry/physics degree. I found it very hard to give him an answer, because there was no practical reason, I was just interested and wanted to learn. As I've aged, I have found that this little bit of knowledge has been invaluable in understanding my world.