The only paid app I've got is Sound Profile. Puts the phone on quiet (except for family) at night, or silent (with auto resume to normal) in meetings. It's on my & spouse's phones.

Yeah, shout out for rsync also. It's awesome. Combine it with ssh & it feels pretty secure too.

A long time ago I was repairing my dad's camera, I found an article describing the exact fault & a link to how to fix it, but the link was dead.

Used the wayback machine to find a text only copy of the fix (no pictures) which was enough.

Was immensely proud that someone had had the idea to invent the IA & have been recommending it ever since.

Not sure if this counts (as a car), but it was a three wheeler (Reliant Robin), gutless and rattly, all the fun of going 50 mph without breaking the speed limit. All the engine weight was directly on the front wheel, so the back end (no weight at all) would slide out wonderfully around corners.