Last winter I got a new touring frame for commuting, so I converted my Italian racing bike to a fixed/single-speed. I really enjoyed it for a while, riding it to work 1-2 days/week. However, my knees didn't like it at all. It is very hilly on my commute route, and apparently my knees just weren't getting enough time to warm up. Long story short, I came close to seriously injuring my knees, and I lost 1,000 miles of riding while recovering. It was an expensive and painful lesson.

I think a lot of the people who get into riding SS/fixed either:
- Live in areas with few or no hills;
- Are a lot younger than me;
- Have much stronger knees than me; or
- Don't ride very much.

I must admit, however, that SS/fixed bikes are appealing. They look great and are easier to maintain due to fewer parts. They are fun to ride because you feel much more connected to the road. They can be inexpensive to build up and maintain.

Just pay attention to your body if you decide to go that route.