In addition to just using a thermometer, many recipes tell you to heat the oil until it starts smoking. So now you know roughly what temperature that is based on the oil used.

If you need to find a substitute for a cooking oil, smoke point is probably the most important factor with which you compare oils, followed by neutrality of flavor.

Aside from using a thermometer, you could also look at the relative temperatures to decide which oil to pick. Olive oil started smoking last time? Try Canola oil or clarified butter for high-temp searing next time. I specifically look at it for picking a suitable choice for seasoning my cast iron pans.

All your stove can tell you is how much heat it's producing. It can't tell you how fast your pan heats up, how long your pan has been on the stove, and whether you just tossed in a half pound of ground pork.

What you can do with this information is see relative smoke points. Unrefined versions of oils have lower smoke points than refined, extra-virgin olive oil has a lower smoke point than peanut oil and canola oil. If you buy an oil at the store that you've never used before, you can check whether its smoke point is higher or lower than the oil you're accustomed to using. If you're in the middle of cooking realize you've run out of everything except the flaxseed oil you've been using for salad dressing, you can look at this chart and realize you should probably run to the store rather than try to cook with it.

Use a thermometer to measure the temp of your pan and/or oil.

Get an IR thermo and make sure you can set the emissivity so that it gives accurate readings for the surface.

Its quick, easy and after some time you will learn to intuit what the temps are without it.

Well, for example, searing meat generally requires temperatures in excess of 350F, so we can immediately conclude that butter and EVOO may not be ideal choices for searing.