I started tracking on FitDay when I started primal, just to keep a rough track of how I felt when I ate certain things, what amounts of fat vs protein vs carbs made me feel good, bad, weak, energetic, etc. Now I feel like I have a pretty good handle on what I should or should not be eating, but I still track because it's become a habit. I don't worry about it, though - I just enter what I've eaten that day and move on. I HAVE been pleasantly surprised a few times, though - I've had a few heavy fruit days where I thought my carbs would be through the roof, but they were still below 100g. So that made me happy.