Heat pot first or is it okay to heat with food? There are a few posts regarding when to add oil to a pan, but I was wondering if the same applied to making soups with a pot.

When making a fresh pot of soup, would I heat the pot first (using the water-drop test), then add, say vegetable oil, then the ingredients? Or does it not matter?

On the other hand, if I'm reheating a soup that I've stored in the fridge, is it okay to heat it with the pot or should I heat it and then add the soup?
First off, when reheating soup, it won't matter much. If you get the pan too hot before you add the soup, you could get some spattering, but that's about it.

As for making a fresh batch, there are those who believe that browning the ingredients before adding the liquids will develop more flavor. This will be a lot easier to do with a hot pan, than trying to get a cold pan full of stuff up to a heat sufficient to cause browning. 

Overall, it's a tradeoff. If you're in a hurry, it might be worth saving the few minutes to just throw everything in the pan and heat it up. If you really want to develop every last bit of flavor, you'll probably be better off heating your pan, browning ingredients, then adding liquid.