A color managed workflow is the cornerstone of any digital photography workflow. I would go so far as to say that a high-end Adobe RGB monitor and a top-notch colorimeter are as important if not more important than what camera and lens you use to capture the image if you care about color.
Greatest achievement. Hard to say, I have had a pretty amazing career, and maybe that is the achievement, still having a career in this very competitive, and challenging industry after 26 years.
I wanted to be an astronaut, a pro tennis player or a photographer when I was in high school. I studied Physics at University because I wanted to be an astronaut but my obsession with rock climbing and mountaineering pulled me towards photography.
Follow your passions. If you want to make it as a pro photographer, you will have to be obsessed. This isn’t a career, it is an all consuming lifestyle. Just like becoming a professional athlete, you have to want a career in photography more than just about anything else to make it happen. How bad do you want it and what are you willing to give up to make it happen?
If you want accurate color and are looking to make print that look like what you see on your monitor then a high-end, accurate monitor that is calibrated and profiled is critical.