I use a 6' one mainly b/c my cat will try to eat the food, but from what I have heard they aren't really necessary. Also if you are shopping for that type of thing consider this water bowl I LOVE it. I only have to change the water every couple of days and my boy likes to dink right from the fountain.
https://www.amazon.com/PetSafe-Drinkwell-Fountain-Multiple-Households/dp/B000FGIUV0