When clients first ask about retirement income, the question is usually phrased as a single number. How much can I draw each year. The honest answer is that the question, as posed, has no good answer.
Retirement is not one event. It is at least three distinct chapters, with three different income profiles, often spanning thirty years. Designing for the single-number version of the question almost always under-serves at least two of them.
Three chapters, three profiles
The first chapter is active retirement. Travel, family, projects long postponed. Spending tends to be the highest, by some distance, of the three chapters. It is also the chapter clients underestimate the most when planning in their fifties, because the activity has not yet started.
The second chapter is the steady middle. Spending settles. Routines emerge. The income required is meaningful but predictable, and most plans cope reasonably well with this stretch. It is the bit financial models flatter.
The third chapter is the later years. Care costs become possible. Spending shifts shape. The income required is harder to forecast in detail, but the plan needs to leave room for it. The cost of getting this wrong is the cost of running out of options at the moment options matter most.
Designing for the shape, not the number
A good retirement plan acknowledges all three chapters in its income profile. It draws more in the active years, allows for steadiness in the middle, and reserves capacity for the later years. It tests itself against poor early returns, longer life, and inflation that does not behave.
What it does not do is assume a single annual figure across thirty years and call the question answered. The shape is the work. The number is the consequence.