I have a 17 month old DS who spends a fair amount of time in the ergo (more for trips/excursions not so much grocery shopping etc now). He's really too heavy to spend much time in the ring sling. I do use it some but it's not really comfortable for more than 10-20 minutes. While the ergo still fits fine now I have a feeling it will be hard to use as I get bigger. What have other people done?