What would be a plausible take on an immortality system if you wanted to make it fair, balanced, and in tune with the nature of life and society?

Let's assume that immortality is potentially achievable by anyone. It is helpful to think of it as a process of incredible difficulty and complexity that requires the help and collaboration of countless individuals.<br><br>Consider how much effort and labor is invested into sustaining the life of one person, even for just 70 years. All the farmers, construction workers, doctors, teachers, and other contributors to society who have all played a role in sustaining that life. How much effort then would be needed to sustain one life for thousands of years?<br><br>If you wanted to make such a system fair and balanced, how would you design it?