[structural]

One heuristic I use to avoid this exact problem is "minimize the number of places that the next poor soul has to look in order to understand how this code works", where place is loosely defined as about the number of lines of code that fit on a screen or two.

This has given really good results in terms of helping decide whether to extract these helper functions or not - they have to both be memorable enough in name and arguments that the code calling them can understand what's going on without always having to dive in, and also provide a meaningful compression of the logic above so that it can be comprehended without having to jump across many hundreds of lines.