What happens if they turn 25 and have grown to expect the nice features? They have more money, less time, and can be a beacon for their peers of "James used to get it for free, now even he pays"
I'd consider it similar to Adobe's old model (easy to crack, but converts to paying customers in a few years)
I'd consider it similar to Adobe's old model (easy to crack, but converts to paying customers in a few years)