Default wrote:
>
> I'm using canola oil in a deep fry machine to make french fries...
> how long should I keep/reuse the oil?

Those are two VERY different questions.

Canola oil in the original sealed container will last years. After
opening unused canola oil still in the container will last a few
years.

The best length of time to use oil in a deep frier is once. Every
time oil is heated it has more transfats. So ideally use as little
as you can and change it daily. As a practical matter consider
changing some of it daily. The more you change the better the fries.