In the mid-90s, Kent Beck introduced the 40 Hours week in Extreme Programming, the idea found space in the principles of the agile manifesto with a broader sustainable development and constant pace which we can summarize in sustainable pace. How has the concept of sustainability evolved in these 25 years? I will share some personal anecdotes on this topic and advanced suggestions borrowed from neuroscience such as flow theory and some of the triggering factors closely linked to other agile principles, I will talk about how the hours spent at work positively or negatively impact private life and vice versa, generating a cycle that can be both virtuous and vicious. Today we also have metrics and tools that help measure and optimize sustainability. Finally, we will reflect on why sustainability will be increasingly important with the evolution of artificial intelligence.