The order in which a recipe introduces ingredients carries as much information as the quantities. Each position reflects a decision about what that ingredient needs to do.
Extraction requires the right medium
Whole spices added to hot fat release aromatics that dissolve in that fat and then spread through the dish, which is a different result from adding them to liquid.
Ground spices burn quickly in the same conditions, which is why they usually appear later, after aromatics have released moisture that moderates the temperature.
Moving either one earlier or later changes what is extracted and how much of it survives, so the position is a technical instruction rather than a convention.
Moisture governs browning
Browning cannot occur while the surface of the pan is wet, since evaporation holds the temperature near boiling regardless of the burner setting.
Ingredients that release a lot of water are therefore placed after everything that needed to brown, not because of flavour preference but because of physics.
A recipe that adds tomatoes before the onions have coloured is either making a different dish or has been abbreviated by someone who did not know why the order mattered.
Cooking rates decide what goes in when
Ingredients reach doneness at very different speeds, and a single pot cooking them together will overcook some unless they are staged.
Dense root vegetables need considerably longer than leaves or delicate proteins, so a well-ordered recipe adds them in descending order of required time.
Where everything is added simultaneously, the dish is usually one where uniform softness is intended rather than one where the sequence was overlooked.
Salt placement changes texture
Salt draws water out of cells, so adding it early to vegetables releases moisture and encourages softening rather than browning.
Applied to proteins in advance, it penetrates and changes how they hold water during cooking, which is the mechanism behind dry brining.
Its position in a recipe therefore signals which of these effects the writer was after, and shifting it produces a different texture even with identical quantities.
Late additions are protecting volatility
Fresh herbs, citrus, ground toasted spice and raw aromatics appear at the end because their aroma compounds evaporate rapidly under heat.
Adding them early does not distribute them better; it removes most of what they were contributing before the dish reaches the table.
Which is why the same herb can appear twice in a recipe, once early for its cooked character and once late for its fresh one.