I just used paper & a pen. I tracked for a few weeks bc my baby was a bit sleepy, had to wake to feed every 3-4 hours. At the start it was actually really helpful bc I was tired, recovering from the birth & couldn't remember what I had for breakfast let alone when I last fed. You would imagine that feeding your baby wouldn't be something you'd forget, but at the start everything seems to run in to each other - feeding, sleeping, nappies, pumping, etc. I found it useful just to monitor how many feeds were had in a 24 hour period, how many wet nappies etc to make sure things were on track.