Happy New Year from New Hampshire!
We've got 3 inches of snow on the ground and patches of ice all over the driveway. Unlike many of you, we heat our house with oil (closer to diesel, really) – yes, we fill up our homes like a car. We're currently burning ~200 gallons a month. That's much more than it takes to keep the lights on here at DQYDJ!
Welcome back to the DQYDJ Weekender. It's been a few months since we last chatted. Let's catch up – and to the roughly 1,000(!) of you who joined the list since then, welcome aboard 📈.
Let's kick it off with some new stuff; I've got a couple new calculators and a visualization many of you asked for:
- Income Growth by Percentile - Did all income growth go to the top? (Spoiler: it's complicated)
- Household Income Growth by Percentile - Same analysis with a household slant. This one's even more complicated... but read it, let me know what you think.
- 3D Treasury Yield Curve Chart - US yield curve data back to 1977 in an interactive 3D view. You can see the inversions, COVID chaos, and the recent path normalization. But seriously, load it and rotate those shapes; it's fun!
I've also got your 2025 return updates. 2025 wasn't as wild as 2024, but it was still a solid year for most asset classes... save the big-two cryptocurrencies:
If you're curious how your portfolio did relative to benchmarks, try the ETF Total Return Calculator, Mutual Fund Return Calculator, or the S&P 500 Return Calculator.
I'm a couple months late on these, but have fun with the new graphs on the contribution limits for some common tax-advantaged US accounts:
- Historical 401(k) Contribution Limit - Every limit since 1978
- Historical IRA Contribution Limit - Every limit since 1974
- Historical HSA Contribution Limit - Every limit since 2004
Deferred maintenance, un-deferred
I (along with my pals Claude, GPT, and Gemini) spent a lot of time on deferred maintenance since we last mailed. I put together new category pages to better show you old posts, tools, and visualizations; tweaked the homepage; and modernized older calculators until I got bored.
Check out /astronomy/, /calculators/, /math/, and /time/
Maintenance with AI-assistance, eh? The famous LLM paper was "Attention Is All You Need." Well, now in 2026 human attention is what we need. I'll get to older tools as I have the time and motivation.
If you have a favorite tool that's old and crusty, let me know and I'll let you put your thumb on the scale. With AI around I can finally pay off a lot of these tool IOUs.
Charity Record
Last edition, I first told you about Charity Record - a tool to track your charitable donations for tax purposes. My update: we launched it to General Availability in December, and it's growing steadily. I'll be tackling some US charity-related content both here and on CR since it's, well, on the brain.
The longer story with CR, if you missed it, is my wife and I were a bit upset when Intuit sunset ItsDeductible in October. We'd been using it for years, and it was a pain to switch to another tool – that pain in mind, might as well build one, right?
Check it out, and pass the link along to anyone you know donating and filing their own taxes. We're mostly at feature parity with ItsDeductible, and we've got some sweet* new features coming soon.
* as sweet as taxes can be, anyway!
On AI
If you've been a subscriber for a bit, you know I waded into AI in a measured and realistic way. I've since fully embraced it.
A couple editions ago, I told you I agreed that if AI development somehow plateaued, it'd still be genuinely amazing as it percolated into the economy. Well, it didn't plateau. If anything, it's still accelerating.
Claude Opus 4.5, GPT-5.2-Codex, and Gemini 3 Pro are all incredible, and a leap forward from the models I was opining on a couple Weekenders back. 2025 was also the year of the Agent – LLMs running tools in a loop until they achieve a goal (or delete their own environment, whichever comes first!). It seems that a harness on these LLMs is what they needed to unlock some productivity.
Claude Code is my daily driver, but I've used all three leading edge US models (and coding harnesses - along with Cursor's) heavily. The deferred maintenance I mentioned here, the new tools, Charity Record – that's tens of thousands of lines of code which would have taken a lot longer to touch before 2025. A lot of it sloggy, sure – you motivate yourself to update hundreds of tools with new JavaScript libraries while removing older libraries like Moment and jQuery. (I'll wait here.)
But still. Before, updating 10-20 calculators was a weekend project. Now it's 10-20 prompts. 10x engineering, indeed!
Look, maybe AGI timelines have leveled off a bit since the 2023 ChatGPT hype. Maybe, as Andrej Karpathy said on Dwarkesh's podcast, "it's a march of nines. Every single nine is a constant amount of work." and we're currently slogging through the nines. And maybe, like Sam Altman told The Verge, "someone is going to lose a phenomenal amount of money."
But the technology is working, and reality is catching up to the hype for my use cases. You should try it for yours.
As William Gibson first put it in 1992 or so: "The future is already here - it's just not evenly distributed."
Value accrues to the appliance makers, not the generators?
Let's speak economically for a minute. What if the value accrues to the appliance makers, not the generators? In this analogy, the generators are the LLMs (electricity), and the appliance makers are the tools built on top of them.
That's not a completely original thought as you know, but it does fly in the face of the "just sell picks and shovels" narrative. If the value accrues to the appliance makers, not the generators, then the generators are going to be the ones losing money... or at minimum not capturing the lion's share of the AI profit.
Right now, though, it seems like the value is accruing to Nvidia. And as I write this, I'm still digesting Nvidia's $20B Groq acquisition – sorry, Groq calls it a "non-exclusive inference technology licensing agreement". That sounds like a lot, and it is... but it was only roughly half of Nvidia's EBITDA last quarter (what?).
Maybe we're looking at a Cisco-in-1999 moment: early rents to the picks and shovels, but the app layer wins later.
(To be clear here: Cisco survived and has now paid off as an investment since March 2000; similarly, Nvidia isn't going anywhere!).
But hey, this is a reasonable thread to pull, and DQYDJ is often an investing site! (See our Investment calculators).
For one data point, Claude Code was Boris Cherny's side project at Anthropic - now it's Anthropic's killer app and getting serious enterprise traction. Will the next killer app add some more evidence here?
Home Updates
I know – seriously, a bunch of you who know me outside of DQYDJ are asking! No need to get mad at me in Slack tomorrow... – you want some home updates.
We got the new Frigidaire Gallery 30" Wall Oven with Pizza functionality over the holidays. For whatever reason it's 3" shorter than our old oven. Now I need to figure out a gap filler... pretty glamorous stuff, eh?
Deck progress: The drink rails are on!
Haha, just kidding, I'm one short – I need to route out a pocket in the bottom of the "wood" of one due to the angle it attaches and the bracket I used. It's too frozen to work on it now... remember that snow I mentioned? Feel free to beat me up in the Spring updates.
What's next, PK? Short list, ask if you're interested: we're having the indirect water heater moved closer to the boiler, and looking at a reservoir for our sometimes low-yielding well. If I plumb one in I'll send you all the ridiculous details. I'll also finish replacing the basement insulation and put the ceiling back up down there.
What's Next on DQYDJ
For the new readers: I know I say "up to once a month" but last year I only sent five of these, so... take that promise with a grain of salt. But the site is always a work in progress... you can visit /blog/ to see what's changing.
For 2026, I'm planning more calculator modernization, and of course revisiting the periodic posts. And yes, yes, it's finally the year we get the next edition of the Survey of Consumer Finances. I haven't forgotten - you will get new Net Worth updates in late fall (most likely), alongside the annual Income updates. Let me know early if you want new angles or topics, and I'll let you know what's doable. I'll definitely add net worth percentile comparison tools and posts as well to match the new income tools, you don't have to ask about those.
Thanks for reading. See you next time – as soon as February, but no promises. Just reply here, or use the contact form if you want to chat. Happy New Year!
