Cognitive load, that is an interesting concept. How to measure it?
One way you could measure it is count how many questions/decisions you must ask and answer when trying to complete a task. The more questions there are the more cognitive load.
I have found in my own work that writing down the questions I need answered helps me make progress in the right dimension. Being explicit about them.
Or how many extra hoops not directly to what you have to get done you have to jump through to get "it" done, whatever "it" is.
ie, rebasing a branch and fixing 10 tests because your 5 days old PR hasn’t been reviewed and there are now conflicts.
Or remembering, each and every time you add a reducer, data source, type, or whatever, to update 5 different lists and enums across to codebase so what you added is properly referenced and used everywhere.
Or deploying by hand by zipping everything and drag and dropping the right files in the right place, put not overwriting the wrong ones by mistake, on a mounted remote server in Windows Files Explorer.
Or, when new bugs suddenly arise out of nowhere, having to test if it actually does come from your codebase, or if it’s actually from _that_ microservice, the one maintained by _that_ team, the one headed by the CTO, that somehow can’t be bothered to have any automated tests in place and yet likes changing and removing "unused" endpoints.
I could go on, and on, and on…
Basically, all the things you have to keep in mind and organise or plan for, even though they are only loosely related to your current focus.
Having a good engineering culture and relentlessly streamlining and simplifying (but not _necessarily_ automating) both codebases and processes helps _tremendously_.
Case in point: CI / CD, automated rollbacks, green / blue deployment, etc.
One way you could measure it is count how many questions/decisions you must ask and answer when trying to complete a task. The more questions there are the more cognitive load.
I have found in my own work that writing down the questions I need answered helps me make progress in the right dimension. Being explicit about them.