12 gallons of peanut oil in R&V Works fryer

I own a 12 gallon Cajun Fryer from R&V Works that I really enjoy using. I'm just never sure what to do with the peanut oil once I've spent an hour or so frying fish, oysters, pistolettes, and boudin balls. Is it best to drain it after each cooking day and discard the oil? How many days should the oil stay good if left in the cooker in non-climate controlled environment? I just don't have the room to store 12 gallons of used cooking oil in a climate controlled space. I hate tossing ~$100 worth the oil after one use.
Any suggestions besides buying a half gallon Fry Daddy?