It is a peculiar kind of madness, isn’t it?
The modern world tells us that “more” is the antidote to anxiety. We are led to believe that a surplus is a shield, and that having a little extra tucked away is the ultimate signal that we’ve finally “made it.”
But for the optimisers among us—the ones who have spent years carefully constructing the pipes, valves, and reservoirs of our financial lives—unallocated money doesn’t feel like a shield.
It feels like a mess.
I call this the Residual Waste Theory.
It’s that nagging, low-level mental friction that occurs when your money doesn’t have a name. It’s the bank-balance equivalent of a “junk drawer” that you can’t quite bring yourself to organise, but you can’t stop thinking about every time you walk past it.
If you are currently sitting in the £10k–£50k bracket of your Financial Independence (FI) journey, you might know exactly what I mean. The foundations are poured. The major leaks are plugged. But suddenly, you’re staring at a few hundred pounds of “residual waste” that is somehow, inexplicably, ruining your weekend.
The 3 AM “Golden Calculator” Award
A few weeks ago, I found myself staring at the ceiling at 3 AM.
I wasn’t worried about debt. I wasn’t worried about the mortgage. I was grumpy—properly, deeply grumpy—because my financial system was running at roughly 91% efficiency.
To a normal person, 91% sounds like an A-grade. To an optimiser who has spent the last year perfecting their money flow, that remaining 9% felt like a neon sign flashing “INCOMPLETE.”
I was lying there, sleep-deprived and irritable, mentally cycling through ratios. If I put 80% of the leftover cash into the ISA and 20% into the savings pot, would that be better than a 70/30 split? What if I moved some to the GIA instead?
I was doing a mental dance with £200, trying to find the “perfect” home for it.
In that moment, I deserved an award. I’ve decided to call it The Golden Calculator for Unnecessary Stress. It’s the highest honour for those of us who would rather lose a night’s sleep than allow a single pound to sit idle without a designated purpose.
The irony, of course, is that the mental energy I was burning was worth far more than the £200 I was trying to “save.”
The 5-Hour “Faffing Tax”
When I finally sat down to audit my grumpiness, I realised I was paying a “Faffing Tax” that was bankrupting my free time.
I estimate I was spending about five hours a week thinking about, tweaking, and hovering over that last 9% of my income. That’s twenty hours a month. Over a year, that is 260 hours of my life—nearly eleven full days—spent staring at a spreadsheet trying to figure out what to do with “the leftovers.”
Think about what you could do with five extra hours a week.
For me, the answer is simple: I want to read more. I want to write more. I want to be present with my child without a ghostly calculator running in the back of my mind.
When we obsess over the Residual Waste, we aren’t just trying to grow our net worth; we are accidentally shrinking our lives. We are trading the very things we are supposedly “buying” with our financial independence—time and peace—for the sake of a marginal gain in efficiency.
The Pareto Principle (the 80/20 rule) suggests that 80% of our results come from 20% of our efforts. In the beginning of the FI journey, the wins are huge. You cut the big expenses, you start the first investment, you see the needle move.
But once you’re in the £10k–£50k zone, the big moves are mostly done. You’re now chasing the “Residual Waste”—that final 9%—and the effort required to “fix” it is vastly disproportionate to the peace it provides.
Defining the “Void” vs. The Joy Fund
There is a distinct difference between “Guilt-Free Spending” and “The Void.”
I’ve spent the last year getting to know my numbers. I know my fixed costs. I know my savings goals. I’ve even carved out a healthy chunk for guilt-free spending—roughly £300 to £500 a month that I can blow on whatever makes life taste better.
But even with that sorted, I was still finding an extra £200 or so at the end of the month.
This was The Void.
It felt like “waste” because I hadn’t given it permission to be spent, but I also hadn’t committed it to the “future.” It was languishing. And because it was languishing, it made me feel like I should be spending it, which triggered a secondary layer of guilt about not being “efficient” enough with my investments.
It was a circular firing squad of logic.
The breakthrough came when I realised that the “Void” was too large to ignore, but too small to be a life-changing investment on its own. It was a middle-child sum of money—neither a splurge nor a pillar of my retirement.
By refusing to name it, I was forcing myself to re-decide its fate every single month. And as any minimalist will tell you, the most exhausting things in life aren’t the big tasks; they are the small decisions we refuse to make once and for all.
Cutting to the Bone: The Automated Slash
At 3 AM, I finally decided to kill the “Residual Waste” at the source.
I stopped trying to find the “perfect” ratio and instead focused on my two highest priorities: Financial Independence and My Child.
I decided to automate the slash.
- £150 goes straight to the investment pot. No thinking. No checking the market. Just gone.
- £50 goes straight to a fund for my child’s future education.
As this is my first child, I have absolutely no idea what schooling costs will actually look like a decade from now. It’s a giant, looming unknown. But by “getting some in now,” I am buying a very specific type of insurance: the insurance against “Future Worry.”
Moving that £50 doesn’t just grow a balance; it quietens a specific part of my brain that used to fret about the long-term horizon.
This move took my system from 91% efficiency to 99% efficiency.
Is it 100%? No. There is still a tiny bit of “dust” left over—maybe £10 or £50 depending on the month. But that tiny bit has been re-branded.
It is no longer “Residual Waste.” It is the Joy Fund.
The Joy Fund is the intentional dustbin for the final 1%. It’s the money that is allowed to be messy. It’s the money that says, “Go ahead, buy that slightly too expensive notebook or the fancy coffee beans.” By naming it, I took the guesswork out of the leftovers.
The stress didn’t come from the amount of money; it came from the lack of a boundary.
The Odd Feeling of Completion
Once I hit “confirm” on those new automated transfers, a very strange sensation washed over me.
It wasn’t a “high.” It wasn’t the rush of dopamine you get from a big purchase.
It was an “odd feeling” of completion. It felt like I had finally closed a dozen browser tabs that had been running in the back of my mind for months.
I realised that I have finally reached the point where I cannot do anything better. The system is as lean as it can be without becoming restrictive. The big rocks are in the jar, the sand is filled in around them, and the lid is on.
For an overachiever, “completion” is a terrifying concept. If the system is finished, what are we supposed to do with our restless energy?
The answer, it turns out, is to live.
I am reclaiming those five hours a week. I am trading the “Golden Calculator” for a pen and a book. I am moving from the “Setup” phase of my life—where everything is about building the machine—into the “Slow Burn” phase, where the machine is running quietly in the cupboard and I am free to ignore it.
If your money is making you grumpy, it’s probably because you’re trying to squeeze 100% efficiency out of a 91% life.
Stop faffing. Name the waste. And then go do something that has absolutely nothing to do with your bank balance.
Gentle Questions for the Road
As the seasons shift and we look toward the next chapter of our journey, I find myself reflecting on how often we use “optimization” as a way to avoid the stillness of having “enough.” It is far easier to tweak a spreadsheet for five hours than it is to sit with the quiet realization that the work is—for now—done.
The “Residual Waste Theory” is really just a reminder that our brains crave order. We don’t need to be rich to be peaceful; we just need to be intentional. Whether it’s £10 or £1,000, giving every pound a name is the simplest way to stop the “mental itch” of a life unmanaged.
As I trade my 3 AM spreadsheet sessions for a few more pages of a good book, I’m noticing a lightness I didn’t expect. The system is finished. The 99% is plenty.
- What “faffing tax” are you currently paying in your own life?
- If you gave your “Residual Waste” a name today—even if it’s just the “Joy Fund”—what specific worry would that quieten for you?
- What would you do with five extra hours a week if you finally declared your financial system “good enough”?