About the Witch
How She Was Conjured
Hi, I'm Dave. I'm an educator, designer and engineer, and I build lots of things. Why this?
I made the CrappyCar Witch because my 2006 Volvo's engine light flickered to life this April (2026). Again. Earlier this year the passenger window fell into the door. Last fall, front end joints and things cost $1,600. The car is expensive to keep — but replacing it is also expensive. I kept asking the same question: which choice is actually cheaper?
There are other calculators, but they weren't clear and they all were designed to sell me stuff. So I built myself a calculator. Then I realized that a lot of people are sitting with the same choice I am. So, the Witch was born!
CrappyCar Witch runs on peer-reviewed research and massive quantities of federal data. It does the math that's easy to skip. What that math actually says — about my Volvo, about your car — is the whole point.
The Witch has opinions about the 2006 Volvo. So does the data.
What She Does
She takes your car — its age, its mileage, its repair history, its mechanic's quote — and runs it against every replacement you're considering. She breaks the total cost of ownership into three phases: the money you spend on day one, the money the car costs to operate over the next several years, and the wealth it quietly destroys by sitting in your driveway and depreciating.
She cross-references your vehicle against NHTSA's complaint and recall database, pulls its fuel economy from the EPA, adjusts maintenance estimates for where you live, and grounds every number in Bureau of Labor Statistics data. Then she tells you what the math says.
And when the math is too close to call — when two options are within the margin of estimation error — she tells you that too. A $300 difference over three years is not a decision the numbers get to make.
What She Isn't
She is not a financial advisor. She is not a mechanic. She cannot inspect the actual car you're looking at; she can only report on the statistical record of its make, model, and year. Her estimates carry real uncertainty — she renders a ±20% band on every projection because hiding it would make her an instrument of the same false confidence she was built to fight.
She asks you to get a pre-purchase inspection before you commit to a replacement. Not because she doubts you. Because she knows what she cannot see.
How She Casts
How She CastsHer tools are not mystical. They are public data, honestly applied.
- Repair & maintenance costs
- Calibrated against national cost data, adjusted for where you live. The Witch knows that a shop in Manhattan charges differently than one in Tulsa — and she accounts for it. Your ZIP maps you to the nearest metro area for the sharpest estimate, with a state average as fallback.
- Reliability signals
- NHTSA complaint database, open recall records, and NCAP crash safety ratings — sourced directly from api.nhtsa.gov. Complaint volume is adjusted for vehicle age and production history, so a popular older model isn't penalized simply for having more time on the road.
- Fuel economy
- EPA FuelEconomy.gov database, matched by year, make, model, and trim.
- Fuel prices
- Weekly retail regular gasoline prices by region from the U.S. Energy Information Administration — updated every Monday, resolved to your PADD region so the math reflects what gas actually costs where you drive, not a national average.
- Depreciation
- Modeled against real-world market behavior across vehicle age, with a floor that reflects actual scrap and parts value. Wealth destruction doesn't go to zero just because a car is old.
- State acquisition costs
- Sales tax rates, registration fees, and average doc fees by state. Insurance figures are directional benchmarks — used to compare options honestly, not to replace your actual premium.
- Geographic reference data
- ZIP code data from SimpleMaps — used to map your ZIP to a metro area for labor rate localization.
The Research Behind the Math
CrappyCar Witch runs on peer-reviewed research — both the numbers (actuarial cost models, fuel decay curves, regional labor data) and the way those numbers are presented (decision science, uncertainty communication, debiasing). Eight academic papers shaped the product's design, and the methodology is documented in full.
The Philosophy
The car industry is structurally designed to make you feel like you have no options. Monthly payments are designed to separate you from the true annual cost. Certified pre-owned programs are designed to make age sound like a feature. GAP insurance, extended warranties, add-on protection packages — every product they have invented exists because the math, done honestly, would produce a different answer.
The Witch does the math honestly.
She is particularly attentive to the psychological traps — the sunk cost fallacy that makes past repair spending feel like justification for future spending, the endowment effect that makes you overvalue your own car relative to what the market will pay, the optimism bias that convinces you the next repair is the last one when the car is simply aging. She will name these things by name, in plain language, because a curse named is a curse weakened.
She is ruthless about numbers and empathetic about everything else. The keep-or-replace decision is made by a real person under real financial pressure, and that person deserves an honest accounting of the costs on both sides — not a pitch.
Standing on the Shoulders of Oracles
Before there was the CrappyCar Witch, there were Tom and Ray Magliozzi — Click and Clack, the Tappet Brothers — who spent 25 years on NPR's Car Talk answering questions from people with failing cars, bad luck, and worse judgment. They made car repair feel like it had moral stakes. They made diagnosis funny. And they understood something most financial tools don't: that a car question is never really just a car question.
Their archive is sacred. When the Witch fails you, consult the elders.