My two have been on it about a year as well. I just switched my 4 year old to the Senior variety as she gains weight too easily due to her bad leg/hip and can't exercise like she needs to and it also contains glucosamine and chondroitin. So far she loves it. I just have spearate bins for their food with their names on it but they look different anyway, the senoir looks like puppy cheerios. Both do very well on it and love it.