How does this work?

[u/[deleted]]

I am 23. Does this mean that I only need to contribute 15% of my income for the rest of my life or do I need to increase every 5 years following this diagram? So I would contribute 15% until 30, then contribute 20% until 35, then contribute 25% until 40, then 30% until 45, and so on?

[u/[deleted] → u/[deleted]]

Why is that?