Do you heat the pan first, then add oil? Or put the oil in and heat up with the pan?

The typical rule of thumb is that if it's a non-stick pan you do add a little oil to the pan first before heating. Most manufacturers usually recommend this to extend the life of the non-stick coating.

For regular pans (those without non-stick coating) you should heat them dry until you can feel the heat radiating from the surface when your hand is held about 6-inches above the bottom. Add your oil at this point. You'll actually need to use less oil because the same amount will spread across a greater surface area due to its decreased viscosity as it heats. Plus, your oil will heat up instantly and when you add your food it's less inclined to stick. Most people get impatient waiting for pans to heat (and in general) and this also ensures that the food isn't going into a pan with oil that's cold or not hot enough. When cold oil goes into a pan and cold food ends up on top of it you'll end up with one big sticky mess. As for adding oil before heating the pan, the longer fats heat without anything else in the pan, the quicker they'll break down and burn.

Always heat the oil with the pan.

Heating pans dry damages the pans (especially non-stick ones). Also, there are no warning signs that the pan is hot when you set something else on it or bump into it.

Adding cold ingredients to hot pans also damages the pan, and can scald the ingredients. Even oil. If you guessed too hot, you can damage several things at once, including the meal.

Oil doesn't significantly degrade through normal heating, and certainly not in a single heat cycle getting up to saute temperatures. If the oil starts smoking (with nothing else in it) yes it's started to degrade but you're also a bit too warm.

Tip: Add some minced garlic or scallions to the oil as it heats. Gives you a nice base for sauteing, and lets you know the oil is up to temperature as they start to cook.

Heat the pan first.

In addition to all the things other people have mentioned, if the pan is slightly damp for whatever reason heating it dry first ensures the oil won't spit as it heats.

Pan first. Heating oil slowly up to temp can degrade the oil. And oil heats faster than metal.

Heat the pan first so you reduce the risk of kitchen absent-mindedness leading to your walking away from a pan of oil over a fire. If the pan is hot, then sautee quantities of oil will get hot basically immediately and you're ready to start cooking.

Don't get the pan too hot, of course.

+1 For all who say pan hot first. Let's talk method.

1. Pan hot -- you can check the heat by dropping a little water in the pan. If it sizzles, you have at least 100ºC in your pan.

2. Put a little oil in the pan to coat it. When the oil looks striated, it's about to burn.

3. Put your food in the pan and be sure you'll get a nice caramelization on your food.

Warning: Depending on the pan, put it on a medium flame, if the pan heats too much, when you put the oil in it will burn almost instantly, and that's not good.

Extra Warning: If you want to use butter instead of oil, use clarified butter.

Put the oil in first.

A comment on your reasoning — the oil will only smoke when it's up past its smoke point temperature. It could sit for a day 10 degrees below that temperature without smoking. If your pan is so hot that it's going to heat your oil past its smoke point, you shouldn't have heated it that high.

For this reason, (the oil will give you early warning by shimmering when it gets close to its smoke point), and because temperature shocks aren't good for pans, I'd recommend to you that you do them together.

Note that you don't always want to add fats in while cold; there are reasons you might want to pre-heat your pan in other situations, but given your question, I'd recommend you put the oil in first.

One of the first things a new cook learns is how to "condition" a pan before sautéing, which is when the cook heats a dry pan and then adds the fat before adding the food product.

There is some science behind this method:

Regarding stainless steel pans, this metal has a grain that is full of pores that will expand to allow the oil to settle in those pores when the metal/pan is dry heated first. If you add oil to cold pan the surface tension of the oil is so great that it will "pool" and rest on top of those poors, when you add protien, the weight of the protein will push the food product into the grain which is not lubricated and your food will stick. This doesn't apply to nonstick pans.

The cookware maker Calaphalon recommends preheating the pan before adding oil and to not use a high heat setting to preheat faster. For more info see: Calphalon Cookware Use and Care.

It depends --

If it's non-stick, I always add the oil early, so I have a warning system if the pan's getting too hot.

For other surfaces, I let the pan heat up before adding the oil.

If I'm not yet ready to use the pan, I typically won't put it on high heat -- I'll put it on medium or medium high (electric stove), so I have less of a chance of overheating the pan (causing instant smoke/burning when I'm ready to use it), but don't have to wait as long for it to get to the optimal heat.

It's my experience that you heat the pan first. There's nothing worse than the smell and taste of burnt oil, especially olive oil.

Sorry, late to the game but I think I have some additional insight. No one has mentioned cast iron skillets and pans and pots. We remember when we were young, when we didn't understand cast iron yet, burning the snot out of that poor, nicely cured skillet mom spent years curing... BAD news, indeed. So I would say this answer specifically relates to the type of pan you are using. No right answer for all pans, and this is a common theme in cooking. I think the other answers covered this already, in terms of stainless and non-stick.

To address the comment, I add oil first, and then heat pan, keeping very close attention to not burning anything.

I use a pan that changes color when it's hot enough. I warm the pan first, and then I add the oil, or butter.

I usually add oil to a cold pan, mostly because I’m never adding just oil; I’m adding garlic or onions or other aromatics which would burn in hot oil instead of infusing the oil with their goodness. If I’m blooming some spices first, the oil gets added after the spices are bloomed.