Writing GUI apps for Apple products. Too many variables to mention, but I wrote my first Apple application in 1986. It took several weeks, and wasn't much to look at. These days, I can spin out a full-fat, shippable app, in a couple of hours. I do that all the time, for my test harnesses.
>> These days, I can spin out a full-fat, shippable app, in a couple of hours. How do you do that? What's your approach?
If you do that, the template is basically a functional app, and you really just need to tweak the storyboard, and supply any ViewControllers. Most of the time spent, is in Adobe Illustrator, generating graphic assets.
Most of my test harnesses are simple, 1-screen apps (with a couple of significant variations). I did, however, use the test harness apps for my BlueThoth library[0], as the starting points for the various Blue Van Clef apps[1] (Bluetooth browser apps for all Apple platforms -yes, you can use your Apple Watch or AppleTV to sniff BLE).
I also have a lot of published modules[2] that help mitigate a lot of the “niggles,” involved in app development. That probably helps a ton.
To be fair, if I am actually shipping an app, as opposed to just using it as a test harness, I spend a lot more time on it, than a couple of hours. I've been working on the app I'm currently developing, for over a year and a half.
[0] https://riftvalleysoftware.com/work/open-source-projects/#bl...
[1] https://apps.apple.com/us/developer/rift-valley-software-inc...
[2] https://riftvalleysoftware.com/work/open-source-projects/