Comment by toast0

I only use mature optimizations, so I'm good.

Thinking about the overall design, how its likely to be used, and what the performane and other requirements are before aggregating the frameworks of the day is mature optimization.

Then you build things in a reasonable way and see if you need to do more for performance. It's fun to do more, but most of the time, building things with a thought about performance gets you where you need to be.

The I don't need to think about performance at all camp, has a real hard time making things better later. For most things, cycle counting upfront isn't useful, but thinking about how data will be accessed and such can easily make a huge difference. Things like bulk load or one at a time load are enormous if you're loading lots of things, but if you'll never load lots of things, either works.

Thinking about concurrency, parallelism, and distributed systems stuff before you build is also pretty mature. It's hard to change some of that after you've started.