I have reused oil before. Our group was not as cautious as Preacher.  For several years our group would take 2 small bottles of oil.  After cooking we would let the oil cool in the skillet and then port it back into the bottle we used first.  We would pore it slow and let the crumbs stay in the skillet. We would fry fish about every other day.  Never had a problem with rancid oil. I do not think oil will go rancid unless there is moisture in it.
I have been the user and care taker of some 500 gallon of canola oil for 10 + years.  It was used for high voltage dielectric.  I had what was not in a sealed barrel filtered annually.  The filtering takes the moisture and particulate out. Last month I gave the oil to another group that wants to use it as high voltage dielectric. I had to pump 100 gallon out of a non sealed but closed barrel where it had been for 2 years with out filtering.  It was not rancid.

MagicPaddler