A good service blueprint summarizes all the big moments that someone goes through when he uses a service. Basically, any service can use the four same big moments or stages.

That's the moment when someone learns that a service exists and maybe compares it with a few other ones. Here you describe how the user gets to know the service: is it via a search on google? Is it his doctor who recommends it to him? 

That's the moment when someone decides to join a service. During that stage, the person might have to create an account, pay, take an appointment, or fill a form. Here you'll also explain what the onboarding process for the user is. 

That's the moment when someone really uses the service and develops a better understanding of how it works. 

That's the moment when someone doesn't need the service anymore and leaves it. 

Many services, like Netflix, are not just one use services but multi-use services. Therefore here you can also show what happens when someone comes back. For example, Netflix shows you the next episode of the series you were watching last time you visited the service.

These four big moments, of a service experience, force you to summarize the complete experience in a simple and efficient way