Life-Long Learning

One of the challenges of being a doctor is that there is always more to learn. There are always textbooks, journals, review articles, new devices, new drugs, new tests, even new diseases. It is an unending learning experience (similar to what medical training feels like). Even as I've become more specialized and focused, I've realized it is impossible to know everything. When I was on PACU, I had time to look at papers, learning modules, and powerpoint presentations. The amount of material out there is overwhelming. I wonder a little if this is similar to other fields; certainly, academicians need to constantly survey the literature and publish, but are there other professions in which life-long learning is a necessity?