Experience is a great learning opportunity, and so is having great teachers.
I've had the fortune and privilege of working with great leaders in many environments—ranging from 10-person startups with no revenue, to global acquirers. I've been on teams challenged by fast, flat, and negative growth; good and bad economies; optimal and non-optimal teams; and a myriad of other circumstances. Every company experiences most of—if not all of—these situations over time as they grow up-market.