I Buy the Same Amount Every Payday No Matter What the Market Does

Every two weeks, on payday, I buy the same thing. Same fund, same percentage, same amount relative to my check. I did it in January 2018 when the market felt unstoppable. I did it in March 2020 when it fell off a cliff. I did it in 2022 when it bled out slowly for twelve straight months. I have never once tried to time it, and I never will.

That's dollar-cost averaging. It's not a strategy anyone brags about at a barbecue. It's boring. But it's the actual mechanism behind almost every dollar of the $781,000 I've built in eight years, and it's the one habit I'd want every soldier reading this to copy before they copy anything else I've written.

The Mechanism Nobody Markets

Dollar-cost averaging means you invest a fixed amount on a fixed schedule, no matter what the market is doing that day. Payday hits, a set percentage of my check routes into TSP C Fund and VOO before I ever see the money in my checking account. I don't check the price first. I don't wait for a "better entry point." The order is already placed by the time I'd think to second-guess it.

The math behind why this works is not complicated, and you don't need to be an analyst to run it. When the price is high, your fixed dollar amount buys fewer shares. When the price drops, that same fixed dollar amount buys more shares. You never buy all your shares at the top, and you never buy all your shares at the bottom — you buy a blend of both, automatically, without having to predict either.

The Math That Convinced Me

Here's a simple version I ran early on, using round numbers close to my own contributions. Invest $500 a month into an S&P 500 index fund for 36 months, starting January 2020 — right before the fastest 30% drop in market history, followed by one of the sharpest recoveries on record. A lump-sum investor who put in all $18,000 in January 2020 would have watched it crater within weeks. The dollar-cost averager who fed in $500 a month bought some shares at the pre-crash high, a lot more shares during the crash in March and April, and the rest on the way back up. By spreading the buys, the average cost per share came in meaningfully below the January 2020 starting price — not because of any timing skill, but because the schedule forced more shares to get bought while they were cheap.

Run that same discipline through 2022, when the S&P 500 dropped about 19% for the year. A soldier who kept contributing the same percentage of base pay into the TSP every single pay period through that entire year bought TSP shares at a steadily falling price for twelve months straight. When the market recovered, every one of those discounted shares recovered with it. The soldiers I've talked to who stopped contributing in 2022 because it "felt bad" missed exactly the shares that would have made 2023 and 2024 pay off the most.

What It Actually Buys You

The real value of dollar-cost averaging isn't the marginally better cost basis. It's that it removes the decision entirely. I saved 50 to 60% of my income for eight years, and the reason I could sustain that rate without burning out is that none of it required a judgment call. There was no morning where I had to decide whether today was a good day to invest. The system decided for me before I woke up.

That matters more in a bear market than a bull market. In 2022, watching account balances shrink month after month, plenty of people stopped their contributions or pulled money out entirely — a decision driven by feeling, not math. A fixed, automatic contribution schedule takes that decision out of your hands on your worst days, which are exactly the days your judgment is worst too.

How I Actually Set It Up

It's three moving pieces, and none of them require willpower after the first setup: a fixed percentage of base pay into the TSP C Fund every pay period, a fixed monthly transfer into a Roth IRA that auto-buys VOO on the same day each month, and any leftover savings routed into a taxable brokerage account with an automatic recurring purchase of VFIAX. I set the percentages once. I have not touched the settings in years except to raise the percentage when my pay went up.

I didn't invent any of this — I read about it in The Intelligent Investor, and the version of dollar-cost averaging Benjamin Graham describes as "formula investing" is almost word for word what I still do every two weeks.

The market doesn't care about your feelings, your timeline, or your read on the news. It doesn't need you to be smart. It needs you to keep buying on schedule for a long time. That's it. That's the whole edge.

Boring on purpose, relentless by design. I'm not trying to beat the market. I'm just trying to never miss a payday.