Before you start to actually sauté your ingredients, you should preheat your pan for a few minutes.
Making sure that your pan is at the proper temperature before adding oil or ingredients.
Meat…As far as cooking meat, heating the skillet before adding any oil or ingredients—such as chicken or pork chop—will mean that your meat will not be as dry as if you had not done this. The reason is that tender cuts of meat needs to be cooked as quickly as possible in order to stay tender.
If your pan is cold when you add your meat, the meat will spend more time over the heat
If your pan is not hot enough when you add your meat, then the meat will just sit there until your pan slowly heats up enough to start cooking the meat.
As the meat just sits there waiting, eventually the juices will start leaking out and then boiling away….resulting in disgusting gray-colored soggy pork chops or tough, instead of tender, chicken.
Veggies...As far as cooking veggies, heating the skillet before adding any oil or ingredients will mean that your veggies will steam them instead of sautéing. This will mean that you will have drab, mushy, overcooked vegetables—not crisp, flavorful and brightly-colored veggies because the veggies have spent too much time over the heat.
How Hot is Hot Enough?…To make sure that your pan is hot enough to add your meat and/or veggies, set a drop of water into the pan. If it’s ready, the water will jump and skitter around on the surface.