I imagine it's like any high(er) level language. You start by writing high-level, idiomatic code, because that's the cheapest to write. If that isn't giving yo

I imagine it's like any high(er) level language. You start by writing high-level, idiomatic code, because that's the cheapest to write. If that isn't giving you the performance you need, then you take steps to incrementally improve the performance without making any radical changes. If that still doesn't get the performance where you need it to be, or you find that you really are having to put the code through a mangler to get there, then, and only then, do you pay the cost of rewriting those components in a lower-level language. IOW, don't take this list as a list of things that you should always do all the time. Take it as a list of specific things to help with solving specific problems, when you have those problems.