As a mentor, I have often discussed with my team the fact that self development is important. I believe that every individual should take 30 minutes out of their working day to self learn. This would include reading relevant articles on the web, reading news sites and even technical manuals.
30 minutes adds up to 2.5 hour per working week. This amount of time is small enough to not make an impact to your working productivity. However, the golden rule is that if you do not take 30 minutes today, you cannot take 1 hour tomorrow. If you miss a 30 minute time slot in one day, you cannot ever make it up, as this could impact your productivity.
Further to this, I also believe in education. People may be an expert in a particular area, but in the current world, progression never stops. If you were an expert in Exchange 2007, well you are now out of date as Exchange 2010 is the latest version, with Exchange 2015 just around the corner.
It is up to each individual to learn and continuously learn and keep up, especially in the IT world. As a Lotus Notes developer I would make sure that I took at least one exam a year. I think in total, I have taken more than 10 exams related to Lotus over the years. Since moving from my technical background into the Project Management arena, I have already taken 3 exams and am now studying for the next.
I feel it is important to learn from a broad range of sources, including books, blogs and related websites. 30 minutes a day is not too much to ask and it pays dividends in your knowledge and overall breadth of knowledge in your chosen area.