Most retirement planning conversations start with a number. "You need R10 million." "Aim for R15 million." Those are lump-sum numbers, and they're mostly the wrong way to think about retirement.
Think in monthly income, not lumps.
What actually matters is how much you'll need to spend, every month, in retirement. Start there and work backwards. Your lump-sum number is just the size of the pile needed to generate that monthly income, sustainably, for as long as you're alive.
A useful working number is the "replacement ratio": the percentage of your final working income you'll need to replace in retirement. The conventional figure is 75%, because some costs (commuting, saving for retirement itself, supporting dependent children) usually fall away. But your own replacement ratio depends on your situation, and can be higher or lower.
From monthly income to lump sum.
Once you know your required monthly income, there's a rough rule: multiply the annual number by 25 to get a ballpark lump sum that can sustain a 4% drawdown rate. So R30,000 a month = R360,000 a year × 25 = R9 million.
This is a ballpark, not a promise. Real numbers depend on drawdown strategy, life expectancy, and market conditions. But it's a useful sense-check, and a better starting point than an arbitrary "you need R10 million" from a proposal.
The number that really matters.
Not the lump sum you've accumulated. The income it would realistically produce, on the day you retire, against the life you want to live. That's the number worth tracking.