I built a car maintenance app that's 1.9 MB. The CARFAX app is 379 MB. I don't know what they know that I don't.
Before writing any code I did something mildly unhinged: I read about four thousand reviews of car maintenance apps, disproportionately the angry ones. The same tragedy over and over, almost word for word — "lost all of my data because the developer didn't offer an export," "after the update I lost all my records," "app is dead, lost all entries, no support." People keep immaculate service history for a decade and then a server migration eats it like it never existed.
So my app has one design rule: you should still have this log in 15 years, even if I get hit by a bus.
Turns out when you take that rule seriously, the app gets small. No account system. No analytics SDK. No ad SDK. No server of mine anywhere — it syncs through your own iCloud, and I could not read your data if you emailed me begging. Everything that bloats an app toward 300 MB is also everything that eventually loses your records or sells them. Delete the whole category and you ship 1.9 MB. The app is smaller than the photo you'd take of your receipt.
What it actually does: service/fuel/expense log, reminders by date and mileage on the lock screen, MPG and cost-per-mile charts, a widget, a glovebox screen for VIN/insurance/registration, and a PDF dossier you hand a buyer. It imports CSVs from Fuelly or a spreadsheet — only a date column required — because switchers shouldn't lose their history either. That's the whole point.
Pricing that would make a VC cry: free for one car, every feature included. $19.99 once for unlimited cars. No subscription — a maintenance log you rent is a log you eventually lose, which would make it the problem I was solving.
Favorite launch-week bug: my CSV importer read a European "9,6" litres as 96, quietly concluding that some poor guy's Golf drinks like a container ship. Fixed in 1.2, along with my assumptions about decimal points.
It's brand new, so the current rating is zero stars from zero ratings. Someone reading this gets to be the first review the app ever has, which is a small, strange kind of power.
App Store: iOS App link — and SteerLog website has free oil-interval and cost-per-mile calculators plus the import guides, no install needed.
Happy to go deep on the local-first CloudKit sync in comments — no server in the loop was the genuinely hard part.