I was thinking of things like: thread-per-client vs C10K. Just go C10K all the way. That means write services to be async, async, async. Just do it. It will not be the case that thread-per-client is better than C10K except when you know you'll only have a handful of clients. Write code to be thread-safe / reentrant. Write code to be separable into libraries.

I'd also urge you to use higher-level languages from the get-go. If you can use Rust instead of C, do it. If Haskell is appropriate, use it. These are all choices that are fantastically easier to make early on than later.

Yes. Some things are just obvious easy wins. And still I am surprised how often we choose to do differenT.

Its the same readon why I almost always immediately use vue or react. Because it doesnt cost me much (~0) but if that thing has to scale i’ll be ready