I found a niche where AI still hasn't shown up: car maintenance tracking

I spent 13 years keeping a paper service book for my own car — writing down oil changes, dates, mileage by hand. When I finally decided to build something, I didn't start with an idea. I started by testing dozens of niches through ASO data: search volume, competition, how weak the current top players actually were.

Car maintenance tracking checked every box. The top 20 apps in the App Store are mostly small players with 0–300 ratings — a real gap, not a hypothetical one. And AI is barely showing up in this space yet. Most competitors still make you type in every field by hand after you take a photo of a receipt, if they let you attach one at all.

So that's what I built Docaro around: snap a photo of any receipt, AI reads it and fills in the record automatically — date, mileage, work done, parts, cost. Works in any language, since I wanted something that'd hold up for people who travel or live in multilingual places. Plus a one-tap PDF export, since "prove your car was maintained" is a real thing that affects resale value.

I'm building this solo, using an AI-assisted, multi-agent dev process I'm still refining as I go.

Curious what maintenance or expense-tracking apps you've personally tried and dropped — and what made you give up on them?