Hi, J. Based on my experiences and those of others I know, your lo may start to resist going to sleep at all for the catnap. That was the case for my dd. She would just cry and cry and never get settled. Although it was tough for her in the beginning to happily make it through until bedtime without the catnap, she eventually adjusted. That was around 5 mos for her, but many keep the catnap for much longer. Also, like you said, a 3rd nap may start to interfere with going to sleep for bedtime. At that point you could try a few days without the catnap and see if that was the culprit. It's trial and error with lo's. Best wishes!