Not using any kind of data made me a better cyclist imo. At my peak this year I rode 80km daily on average and pretty fast. Keep in mind that I was overweight at that point, started out obese this year and that I've never been fit in my entire life. If you only listen to your body your body will take you close to its limits. The first time I felt that my mind wasn't capable of keeping up with what my body wanted to do was on my first 120km ride.
Currently I'm more focused on running and I'm still figuring some stuff out. I think I just got my diet right.
But I'm starting to look for fitness trackers now as I think that I'm getting to the point where I'll run into a barrier without tracking my performance in the foreseeable future.