On the 21st of every month, my phone buzzes with the same notification: my salary has landed. And within about an hour, a big chunk of it is already gone — automatically moved into my retirement savings account and used to buy the same handful of funds I always buy.
I don’t check the price first. I don’t read the news to decide whether “today is a good day.” I don’t ask myself whether the market is high or low. I just buy. About $1,300, every single month, whether the headlines are cheerful or terrifying.
And “I just buy” is almost the wrong way to put it — because I don’t actually lift a finger. The whole thing runs on autopilot, in two steps. On payday, a fixed amount is automatically transferred from my paycheck into my retirement account. Then, as soon as that money lands, it automatically buys my ETFs. No button to press, no decision to make, no window in which I could talk myself out of it. I built it this way on purpose, because I’ve come to hold a deep, almost stubborn belief: steady, long-term, automatic investing simply does not betray you. Over a long enough horizon, it does not fail.
That habit has a name. It’s called dollar-cost averaging, or DCA for short. And honestly, it might be the single most boring thing I do with my money. It’s also, I’ve come to believe, one of the smartest.
Let me explain what it is, why it works, and why it fits a regular working person like me so well.
What dollar-cost averaging actually means
Dollar-cost averaging is simple: you invest a fixed amount of money at regular intervals, no matter what the price is doing.
Instead of trying to guess the perfect moment to jump in with a big pile of cash, you break your investing into small, steady, repeating purchases. Same amount, same schedule, over and over.
Here’s a tiny example. Imagine you invest $300 a month into a fund, and over four months the price per share bounces around like this:
- Month 1: price is $30 → your $300 buys 10 shares
- Month 2: price drops to $20 → your $300 buys 15 shares
- Month 3: price falls to $15 → your $300 buys 20 shares
- Month 4: price recovers to $25 → your $300 buys 12 shares
Over four months you invested $1,200 and ended up with 57 shares. Your average cost per share was about $21 — even though the price averaged around $22.50 over that period.
Notice something interesting: when the price fell, your fixed $300 automatically bought more shares. When the price rose, it bought fewer. You didn’t have to be clever. The math did the work for you, buying more when things were cheap and less when they were expensive. That’s the quiet magic of DCA.
Why this suits a working person perfectly
Here’s a truth that a lot of finance articles skip over.
There’s a famous piece of research from Vanguard that compared investing a lump sum all at once versus spreading it out over time. The conclusion surprised a lot of people: putting the money in all at once actually won about two-thirds of the time. Because markets tend to rise over the long run, being invested sooner usually beats waiting.
So if lump-sum investing wins more often, why do I use dollar-cost averaging?
Because I don’t have a lump sum. And neither do most people who work for a paycheck.
I’m not sitting on a giant pile of cash wondering how to deploy it. I get paid once a month, and I invest a slice of that paycheck as it arrives. For someone like me, DCA isn’t really a strategy I “chose” over lump-sum investing — it’s simply the natural rhythm of investing money as I earn it. The choice isn’t “lump sum vs. DCA.” The real choice is “invest this month’s money, or don’t.” And I always choose to invest.
That distinction matters, and I want to be honest about it. If you ever do receive a big one-time amount — a bonus, an inheritance, a payout — the research suggests that investing it sooner rather than dribbling it in tends to do better on average. But for the steady monthly saver, DCA is just how the game is played.
What the research actually says about lump sum vs. dollar-cost averaging
I said above that if a big one-time amount ever lands in your account, investing it right away tends to beat dribbling it in. That isn’t my hunch. Vanguard tested it.
Their researchers compared the two approaches across the US, UK and Australian markets over rolling periods going back to the 1970s. Investing the whole sum immediately came out ahead roughly two-thirds of the time — about 67% in their original study, and somewhere between roughly 62% and 74% depending on the market in later work covering 1976 through 2022. For a balanced 60/40 portfolio, the average edge over a twelve-month averaging window was a little over two percentage points. You can read Vanguard’s own summary of the work here.
The reason isn’t complicated. Markets rise more often than they fall. Money parked in cash waiting for a nicer entry price spends most of its life not earning anything.
So why do I keep doing this? Because that finding is about a pile of money you already have. I don’t have a pile. I have a paycheck. For me the question was never “lump sum or DCA” — it was “invest this month’s money, or don’t.”
But it does settle one thing. The next time a bonus lands, I already know the honest answer: put it in, and don’t congratulate myself for waiting.
The real reason I love it: it protects me from myself
I spent years working on ships and at industrial sites, and if there’s one thing that environment teaches you, it’s respect for a good checklist and a steady routine. When something is automatic, you can’t skip it on a bad day. You can’t talk yourself out of it.
That’s exactly what dollar-cost averaging does for my investing. It removes the two most expensive words in personal finance: “not yet.”
Think about how most people fail at investing. It’s rarely because they picked the wrong fund. It’s because they get scared when prices fall and stop buying — right when things are on sale. Or they get greedy when prices soar and pile in at the top. Emotions push them to buy high and sell low, which is the exact opposite of the goal.
DCA quietly disarms all of that. When the market crashed and everyone around me was panicking, my automatic purchase went through anyway — and it bought a bunch of shares at low prices. When the market was euphoric and tempting me to throw in extra, my fixed amount kept me disciplined. I’ve stopped trying to outsmart the market. I just show up, every month, on schedule.
And over the long run, showing up is most of the battle. The S&P 500 has returned roughly 10% per year on average since 1928. That average includes the Great Depression, wars, oil shocks, the 2008 crisis, and the 2020 crash. The people who captured that long-term return weren’t the geniuses who timed every dip. They were the ones who kept buying through all of it.
How I actually do it
My setup is deliberately dull, and that’s the point:
- It’s fully automatic — in two steps. The paycheck transfer into my retirement account and the ETF purchase inside it both happen on their own, without me lifting a finger, so my mood on any given day is irrelevant.
- It’s the same amount every month. No agonizing over whether to invest more or less based on a hunch.
- It goes into broad, low-cost funds centered on the S&P 500, so I’m buying a slice of hundreds of companies at once instead of betting on any single one.
- I don’t check it constantly. Watching the balance every day just tempts me to tinker. The routine works best when I leave it alone.
That’s it. There’s no secret sauce. It’s a boring habit repeated with stubborn consistency — the financial equivalent of brushing your teeth.
Where the $1,300 actually goes
“I buy the same handful of funds” is true but vague, so here is the actual plumbing.
The money doesn’t land in an ordinary brokerage account. It goes into Korea’s tax-advantaged retirement accounts first, because inside them each dollar is worth more than a dollar.
Korea hands that benefit over as a tax credit — money refunded at year-end settlement — rather than as a deduction from taxable income the way a traditional US 401(k) does. Fill the annual ceiling and a meaningful chunk comes back every single year, before the market has done anything at all. There is no fund I can reliably pick that beats a certain refund.
So the ceiling is the first thing my automatic transfer fills, every year. It is the least controversial decision in my entire financial life, and it’s why I don’t agonise over what the market did last week.
Only after that does anything go into a regular account. If you want the detailed version — how the Korean accounts compare to a 401(k) and an IRA, what the actual limits are, and why the American system produces so many more millionaires — I’ve written about that separately in The Secret Weapon Behind America’s 401(k) Millionaires.
What $1,300 a month actually becomes
This is the part I find genuinely motivating, and it’s also the part where personal finance writing usually starts lying. So let me be precise about what this is: arithmetic, not a forecast.
Below is what my current balance of about $106,000 plus $1,300 a month turns into, at two assumed rates of return. I’m showing 6% and 8% because the honest answer is that nobody knows, and the range matters more than any single number.
Look at the gap between the grey bars and the blue ones. At year five the market has added something like $50,000 to $70,000 — noticeable, but most of the balance is still just my own money piling up. By year twenty, growth contributes more than everything I ever deposited. That crossover is the whole argument for starting now instead of when you feel ready.
Now the caveats, because that chart is a smooth curve and reality is not. Returns don’t arrive at a steady 6% or 8%; they arrive as a violent scribble that happens to average out. The figures ignore inflation, so the year-twenty number buys considerably less than it looks like it does. They assume I never stop contributing, never panic-sell, and never need the money early. And they use a fixed exchange rate of ₩1,500 to the dollar, a simplification I make everywhere on this site so month-to-month comparisons stay readable.
The chart isn’t a promise. It’s the reason I don’t interrupt the automatic transfer.
When dollar-cost averaging works against you
If a strategy has no downside, you’re being sold something. Here are the real ones.
It is slower in a rising market. That’s the Vanguard finding above, restated. If you hold cash and feed it in gradually while markets climb, you end up behind the person who invested it all at the start — roughly two times in three.
It doesn’t protect you from a bad investment. Buying something terrible at regular intervals just means losing money on a schedule. DCA is a decision about timing, not about what you own. The only reason I’m comfortable buying on autopilot is that what I’m buying is a broad index of hundreds of companies, not one stock I’ve talked myself into.
It can become an excuse. “I’m dollar-cost averaging” sounds disciplined, but it can also be what someone says while keeping most of their money in cash indefinitely because committing feels frightening. Averaging into the market over six months is a plan. Averaging in over six years is usually avoidance wearing a plan’s clothing.
It requires the one thing that is genuinely hard. The mechanics are trivial. Continuing through a 30% drawdown, while every headline explains why this time is different, is not. The automation exists precisely because I don’t trust my future self to make that call in the moment.
Questions I get asked
How often should I invest — weekly or monthly?
It matters far less than whether you do it at all. I transfer monthly because I’m paid monthly, and the buying is spread across the weeks because my provider offers it that way. If yours charges per transaction, fewer and larger purchases are better. Don’t let this question delay you by a year.
Should I stop buying when the market is at an all-time high?
Markets spend a surprising share of their lives at all-time highs — that is what a long-term uptrend looks like from the inside. Waiting for a dip means holding cash for an unknown length of time in exchange for an unknown discount. I have never once paused my transfer for this reason.
What if I can only afford a small amount?
Then start with the small amount. Early on, the habit and the account matter more than the size. The amount tends to grow with your income; the habit is the hard part. My own contribution was a great deal smaller when I began.
Does dollar-cost averaging work for individual stocks?
Mechanically, yes. But it doesn’t fix the underlying problem, which is that you still have to be right about the company. I stopped picking individual stocks because I wasn’t good at it, and I’d rather say that plainly than pretend otherwise.
Where does the money actually go, in Korea?
The pension savings account and IRP first, up to the ₩9,000,000 that earns the tax credit, for the reason in the table above. Anything beyond that goes into a regular account.
The takeaway
Dollar-cost averaging won’t make you rich overnight, and it won’t win you bragging rights at a dinner party. What it will do is keep you invested, keep you calm, and keep your emotions from sabotaging your future. For a regular working person building wealth one paycheck at a time, that’s not a consolation prize — that’s the whole game.
Every month, my phone buzzes, the money moves on its own, and a few more shares quietly join the pile. It’s not exciting. But four years from now, and forty years from now, I think the boring version of me will turn out to have been the smart one.
This post is part of my honest, public journey from roughly $96,000 in savings toward $100,000 a year in passive income. I’m a 40-something engineer, not a financial advisor, and nothing here is financial advice — it’s just what I’m doing and what I’ve learned. Please do your own research before investing.