When to add oil to the pan is one of the greatest little debates in cooking. Does it go in right away so it can heat with the pan? Or do you let the pan preheat first so you can gauge the heat by how the oil flows across the bottom of the pan when you pour it in?

Like many culinary conundrums, there’s no firm answer here that can be applied to every situation. But there are best practices that you can follow, depending on the type of pan you’re using. Here’s everything you need to know about when to add the oil immediately—and when it’s okay to wait.

Nonstick

Unless the prospect of hazardous chemicals in the air excites you, you’ll want to add oil or another cooking fat to a nonstick pan before turning on the heat. Heating an empty nonstick pan can cause the coating to release toxins into the air, which is … obviously not ideal. Also, warming the fat or the oil in the pan as it preheats can also help double down on the pan’s nonstick properties, which is a big bonus.

When To Add Oil To Every Type Of Pan, According To Experts

Enameled Cast Iron

You should also never heat an enameled cast iron vessel empty—but for a completely different reason. When an enameled cast iron pot or pan is heated over direct heat (such as on a stove top burner) without anything inside it to disperse the heat, the unevenly applied direct heat may cause the enamel coating to chip and crack, or even split apart completely. This happens because the cast iron expands faster than the layer of enamel coating.

Adding something to the pan, whether that’s oil or another fat helps to disperse the heat evenly around the pan, preventing uneven heating. The bottom line? If you want your expensive (and super heavy!) Dutch oven to last that proverbial lifetime, make sure there’s always something in it when you set it on the heat.

When To Add Oil To Every Type Of Pan, According To Experts

Cast Iron

Plain cast iron? Completely different situation. If there’s no enamel coating, free to heat these pans with nothing at all inside. Keep in mind, though, that excessive high heat might dry out the cast iron surface over time if you don’t moisturize the pan between uses. If you’re in the habit of using your pan often for dry heat cooking, such as toasting spices or charring whole veggies, it might be wise to rub it down with a little oil as it’s cooling.

When To Add Oil To Every Type Of Pan, According To Experts

Stainless Steel

This one is the biggest source of debate, and you’ll find culinary professionals on both sides of the subject. The bottom line? As long as you’re heating on medium heat just until the pan is hot, you don’t need to have any oil or other fat inside the pan. If you’re unsure of how hot the pan is and don’t want to add oil blindly, try flicking a little water onto the pan’s dry surface. (Do NOT do this if there’s any fat at all in the pan). If the water droplet dances, the pan is ready for the cooking oil. If it spits or sizzles aggressively, the pan might actually be too hot, in which case, I’d recommend pulling it off the heat until it cools down a little.