@spencer Preheating the pan stops food from sticking but garlic and onion never sticks for me so I don't think in this case it makes any difference.

Taking this further my mother would always follow recipe steps correctly while her sister just turned on the heat, chucked everything into the pot at once, and put the lid on. My mother hated that it was usually just as good.

@spencer I remember learning to heat the pan, then put the oil in, then put the stuff in from the show Salt, Fat, Acid, Heat.

I don't remember the rationale though.

I think you should each cook the same dish with your different methods and have a third person arrange a blind taste test for you two and see which you prefer. 😁

@spencer cooking the onion garlic and oil together allows the onion and garlic flavors to come out whereas if you heat the oil first and then add the onion and garlic you're essentially searing the garlic and onion trapping their flavors inside, it really depends on the dish you're cooking and it's home base cooking is more of a personal choice on how you cook, but on average if you put those initial ingredients in the cold pan with the oil you give them far more opportunity to let the flavors come out and mix with everything else that you're cooking, just my two cents;