This was my first time cooking sous vide. I highly recommend this cooker if you are wanting to try sous vide. You must use your phone if you want to use the timer function. Although, this is not really necessary. The timer doesn't stop the cooking process. It just lets you know then the time expires. If you want to use the timer, you set the time and temp on your phone and tell it to start. The app will tell you when the water is heated to the desired temp and prompt you to put in your food. Only after clicking ok does the timer start. I have mostly just put my food in the water out of the tap, start it, and walk away. I lose the timer function but that not a big deal. You may want to consider paying the extra money for the wifi version. I wish I would have. It would be nice to be able to start a 4 hour cook from my office so it's ready when I get home.