Track 14 · Enough · lesson 2
The spending side moves the goal faster
11 min
Track 14 · Enough · lesson 2
11 min
There are two ways to close the gap between where a pile is and where it needs to be. Put more in, or need less out.
They are usually presented as equivalent — two sides of the same surplus. They are not equivalent, and the reason is that one of them moves the finish line and the other does not.
A permanent reduction in spending does two things in the same movement.
It raises the surplus this year, by the amount saved. And it lowers the target for every future year, because the target was the spending divided by a rate.
A raise does the first of those and not the second. It puts more into the pile and leaves the required size of the pile exactly where it was — and if the raise is spent, it moves the required size in the wrong direction.
Take an ongoing cost of 100 a month. That is 1,200 a year.
The surplus effect is 1,200 a year, which is the number people see.
The target effect is 1,200 divided by whatever sustainable rate you assumed. At four percent that is 30,000. At three percent it is 40,000. The finish line moved by thirty or forty times the annual amount, permanently, on the day the cost stopped.
Predict
The model holds the pile at 500,000 and the assumptions fixed. The only control is how much comes out each year, expressed as a share of the starting pile.
Withdrawal sustainability
Hypothetical model, not a forecast
How long a portfolio lasts at a chosen withdrawal rate, and the rate that would last forever.
It assumes
It ignores
Bring the spending down until the pile is larger after thirty years than it was at the start. Note how close that point is to the net return after the fee.
A share of the starting portfolio, held flat in real terms thereafter.
| Year | Balance | Taken out to date |
|---|---|---|
| 0 | 500k | 0 |
| 1 | 487k | 25k |
| 2 | 474k | 50k |
| 3 | 461k | 75k |
| 4 | 447k | 100k |
| 5 | 433k | 125k |
| 6 | 419k | 150k |
| 7 | 404k | 175k |
| 8 | 389k | 200k |
| 9 | 374k | 225k |
| 10 | 358k | 250k |
| 11 | 341k | 275k |
| 12 | 324k | 300k |
| 13 | 307k | 325k |
| 14 | 290k | 350k |
| 15 | 272k | 375k |
| 16 | 253k | 400k |
| 17 | 234k | 425k |
| 18 | 214k | 450k |
| 19 | 194k | 475k |
| 20 | 174k | 500k |
| 21 | 152k | 525k |
| 22 | 131k | 550k |
| 23 | 109k | 575k |
| 24 | 85.7k | 600k |
| 25 | 62.3k | 625k |
| 26 | 38.2k | 650k |
| 27 | 13.6k | 675k |
| 28 | 0 | 689k |
| 29 | 0 | 689k |
| 30 | 0 | 689k |
Not there yet — keep moving the controls.
The crossover sits at about two and a half percent, a shade under the net return of two point six. That gap exists because money taken out at the start of a year does not get to grow during it.
Cut the spending by a fifth and the same pile goes from shrinking to growing. Nothing about the returns changed.
Not the same thing
Money spent once, on a thing that does not recur — a trip, a repair, a purchase.
Money committed every month or year, usually attached to a contract, a home, a vehicle or a subscription.
Which is which? Put each one on a side.
A larger fixed housing cost taken on after a raise
Replacing a broken appliance
Four subscriptions nobody has looked at since the year they started
A holiday paid for out of a surplus that was already allowed for
Two limits, and both are real.
Costs have a floor and income does not. Below some level, spending is housing, food, heat and transport, and further reduction stops being a financial decision and becomes a worse life. The multiplier is powerful in the range where spending is discretionary and it does not exist below it.
The effect is a one-way ratchet in reverse. A cost removed and then reinstated gives the target effect back in full. The gain comes from the cost staying gone, which is a behavioural question rather than an arithmetic one.
And a third, which is the whole point of this track: a plan optimised purely downward arrives at a small number and a life nobody wanted. Enough is defined by what it is for, and cutting past the purpose defeats the exercise.
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