A few years ago, I wanted to loose 10 pounds, so I started measuring/weighing everything I ate and counting calories. I was shocked to find out that many of my days were well below 1000 (I've never really had a huge appetite). I also had a lot of days when I didn't feel well. Guess what? Those were the days when I didn't eat enough.

So now I track calories to make sure that I eat enough. Riding 60 - 80 mpw and maintaining a generally active lifestyle (read: very little TV and no personal car) I've found that I need about 2200 calories/day to feel good and maintain my weight. At this point I've measured enough food that I can eyeball portions pretty well, but every so often I go back to measuring and recording everything for a week or two just to check in with myself.

FWIW I find that I feel better and have an easier time making my calorie counts if I eat the same number each day. Adding more calories on days that I took long rides just didn't work for me; I didn't have energy when I needed it, and I absolutely starved on rest days. When I've used software or online trackers like MyPlate, this means that I set my base activity level to be higher and don't record exercise at all.

At 150-200 mpw, 3000 calories sounds just about right to me, but I'm sure that a nutritionist would have a more informative opinion.