To stay with the fond analogy: It gets interesting if the fond preparation involves deglazing a pan (mutable environment) with meat bits and juices left at the

To stay with the fond analogy: It gets interesting if the fond preparation involves deglazing a pan (mutable environment) with meat bits and juices left at the bottom (state/precondition). Two options: - Linear code: The meat frying (state-producing) and deglazing (state-requiring) steps are below each other in the same recipe, so to verify that it works you can just linearly go through line by line. However if the recipe becomes long and a lot of stuff happens in between, it's no longer obvious. You'll have to use good comments ("// leave residue in the pan, we'll need it for the fond") because otherwise you might accidentally refactor in a way that violates the precondition (swaps/scrubs the pan). - Modular code: You need to clearly describe the precondition on the fond preparation subroutine to have any chance to keep using it correctly. On one hand this forces documentation, on the other hand it's probably still easier to forget since the subroutine call ("Prepare the fond.") doesn't directly make the precondition obvious. Either way has its advantages and drawbacks, and the right choice depends on the circumstances. This is assuming you only want to cook this specific meal and aren't writing a cookbook - otherwise you should definitely modularize to remove repetition.