Carpet

I finally broke down and went to a spin class. As I was getting ready I realized I don't have a heart rate monitor anymore. All I have is my Garmin Edge which really doesn't work well in a spin class. I guess I'll have to look for a cheap monitor to use in classes but I'm really not sure I need one. I was pretty much able to tell what zone I was in during the whole class (I tried to stay in zone 1 and 2 since I'm building a base). Even when I race I rarely look at my heart rate and really the only information I care about in a race from the Edge is was I faster or slower then last year? And in the case of endurance races how much time did I stop?