Why one “corpus number” is not enough

Markets don’t move in a straight line

Most simple projections assume a steady return year after year. In practice, sequence matters: early bad years near retirement weigh differently than the same average return smoothed over decades. One fixed corpus figure rarely captures that.

Inflation and spending aren’t fixed either

Your future spending in “today’s rupees” is a guess. Long-run inflation is uncertain. A single nominal target often bakes in one scenario for both. Stressing a band (lower / base / higher) is usually more honest than defending one cell in a sheet.

What to do instead

You don’t need a PhD—just a habit:

• Separate lifestyle spend from corpus math and revisit both periodically.
• Ask what happens if returns are a few points lower for a decade, not just in one average cell.
• Prefer “chance of hitting the goal by target age” (or time-to-target under stress) over a single yes/no line.

Our FI planning guide walks through corpus and inflation in more depth; this post is only the framing.