As an example, we often lightly fry onions in (preferably) Olive Oil before adding them to any number of dishes, such as scrambled eggs for breakfast.
My talented cooking friends frequently remind me, "Don't put your veggies into the frying pan until the oil is hot!" The thing is, I personally can't tell the difference if I put my veggies in immediately after adding oil to the pan, or if I wait for the oil to properly heat up first. My friends also tell me, "Don't turn the heat up all the way either!"
Why do people recommend heating the oil first? Are there really benefits to waiting the 3-5 minutes?
If the answer to above is yes, how high should you turn the heat up to get the oil? Can I just set it to 100% for 1 minute to cook the oil faster? Yes I realize I have to watch the oil carefully otherwise chaos will ensue.