You can keep and reuse oil for quite a while. There are issues though.
Refrigeration helps as does filtering wayward food particles. Over time though oil can and will get rancid. Not good.
To "freshen" used oil fry up a big batch of taters. (Darn the luck, French fries)
. Really, it does work to remove "off" flavors from used oil. Might not be the best fries you ever had but hey, you can use your oil for a few more passes.
Peanut oil is great because of the high smoke point. That means you can fry @ 360 - 370 without setting off the smoke alarm.
Do be aware of prospective diners that may have a peanut allergy. It could be bad.