It depends. If you bake bread every day or use your sourdough starter every day, then yes, you need to feed it every day. If you only use it once a week, then no. 1. If you leave it on your counter all of the time you must feed it to keep it alive. You also need to use it (or discard some) so that it doesn't just keep growing. If you are baking with it every day, you don't need to worry about it growing. Just feed it daily and use it daily and it'll be fine. 2. If you don't want to use it daily, but say, once a week, put it in the fridge fed. I put mine in a mason jar with a lid and keep it in the back of my fridge until I need it again. The coolness of the fridge slows down the GOOD bacteria in the starter and makes it so it doesn't feed on the flour as quickly. This means that you can keep it in your fridge for a week or two without feeding it and it'll be fine. Once you are ready to use it again, pull it out, feed it and let it get active (bubbly) and it'll be good to use again. Make sure you do feed it prior to putting it in the fridge so that it does have something to keep it alive while in there.