What is your association's membership niche? That's the real question, whether it's animals, a professional society or even a trade association. Your association specializes in your niche. You may not have gone to school for your association's industry but the amount of years you have spent working as a professional with this organization has made you a fast expert in your industry.
Association's often outsource because they know that vendors have their niche. WebLink International, my current employer has a specialized niche in association management software and websites. My previous employer specialized in career centers for non-profits, while the associations I worked for were trade associations and professional societies. Throughout my adventures, I have picked up a few skills that I wouldn't have if I had worked other places. However, I am still faced with the fact that I know that there is a better way to do this, and quicker.
At one of my employers, I was responsible for doing graphic design. This was not in my immediate skill set, and I made no secret of it. However, I was willing and eager to figure it out, and take the time to do so. I learned the very basic elements of graphic design, and could change layouts, and other things quickly. Starting from scratch without an idea of where to go, now that was a real challenge. What this made me understand is that sometimes, while it's cost effective it's best to not go it alone and engage experts where your budget and project needs fit. Often times, the items that I designed from scratch took a long time to produce, and I always thought they could be better if this was in my skill set.