First of all, I know Costco sells it in large jugs. You'll have to call them for a price.
I have a deep fryer that does not leave my counter top and it is filled with peanut oil.
It does seem to hold up better than the vegetable oils and NO...you do not have to change it out every time. I frequently strain the oil after its cool and reuse.
I pitch mine out when it has become too dark, which also means (more than likely)it's begining to leave an undesirable (burnt) flavoring.
It also breaks down, doesn't burn as hot as it should and therefore, leaving the food too greasy.

Frying coated fish ruins the oil the fastest.