With create-react-app, it takes less than a few seconds, if you're fine with their defaults. If you need to mess with the webpack config it will take a bit longer but once you do it the first time its not a big deal. Putting everything together from scratch would take awhile, but that's the tradeoff of having a really flexible modular system.

I usually count on a week to boilerplate a new application. I find that spending that time to do things in a more hand-crafted way is made up for my having a consistent implementation where the structure and code make sense. Glad to see more projects moving away from `./test, ./scripts, ./views, ./styles` structure.

that's fair - I built a react app for my company's website which is statically generated (a twist on server-rendering), and that took about a week to boilerplate. Next time I do it though it will take no time at all.

True, as long as you're using the same versions of the tools... I find that even after a year, if I'm boilerplating something out, even if similar, it's still about a week. The tools change, and APIs between versions break. I had to deal with a react-router change between the last beta and the final 4.0.0 just yesterday (this.context.router.push vs this.context.router.history.push). I tend to mostly lock down my versioning on things to a large extent as a project matures... but even keeping up is more organic.

Starting something new in a year, or 18 months can be dramatically different than the previous start.

Well, some minutes with npm. With yarn, it might take a few seconds.