What would you rather be: a expert specialist in some narrow area of SQL Server or a generalist that's competent in many areas? The same question could apply to any area of technology, like C# or Windows, or even any subject in which you work. What's your preference?

Most of us don't have to make a strict choice. Often in pursuit of deep knowledge in one area, say indexing, the effort will lead to lots of good general knowledge in other parts of the platform. I think it's important that gain both types of skill, as you work through your career and grow your abilities. I find that there is always more to learn, especially in technology. Even in areas that I think I have deep knowledge about, I continually add to, and refine, my skills.

Brent Ozar had an interesting post on this topic, looking at the maturity of a particular subject area. He noted the more mature some area, the more you might learn towards specialization. I think that's good advice for your career, though I do think that if you find a deep passion, don't be afraid to specialize in some area. While you might not get a monetary compensation directly back for the effort put in, I think the reward of learning something you love, and achieving expertise is extremely valuable and important to you as an individual.

As we move through our careers in computing, we find there are always new technologies, techniques, and architectures that we will need to understand. We need to grow our knowledge. In many cases we see older ideas re-packaged and updated for the modern times, but that doesn't mean skills we can rely on prior knowledge. Instead, you will need to update your skills.

I also think more and more we will be driven to give guidance to others as much as use specific expertise to solve problems. With that in mind, I think whether you choose to be a specialist of generalist, you'll need to continue to learn more about both implementing technology, as well as communicating your recommendations.