Co-founder relationships change with age. 7 Founders over 30 are 40% more likely to be solo founders than their younger peers. But even when they do have co-founders, their relationships are still different. They tend to have calmer, more collegial connections with their co-founders. By comparison, twice as many founders under 30 say their co-founder relationship is strained. But they also say they're best friends with their co-founder 33% more often than their older peers.