When pan searing, why does all of my oil keep disappearing?
If the oil is of too low temperature, it'll have a tendency to get soaked up by the food you're preparing or get evaporated together with the water that's leaking out, so that's where it's disappearing. (Some vegetables like eggplant, zucchini, ... tend to soak up oil like sponges regardless of the temperature.)

To test whether the oil is hot enough, I always use the empirical method:


slice off a sliver of whatever you're going to sear
throw it in the pan


if bubbles start forming: oil is hot enough
if not: throw away sliver, rinse and repeat



Works for anything  you're going to sear!

Having said that: Don't be shy on the oil: it doesn't just sear, it adds flavour too!