I have a large deep fryer that I sometimes use the oil multiple times over a number of weeks period. . . I’ll confess. . . sometimes it’s a month or so.
I don’t think you can do that without covering the oil soon after you turn the heat off. If any airborne bacteria got in there it would probably go rancid fairly quick. I have a metal cover for mine.
I’ve never found the tastes that get mixed up to be offensive. My daughter won’t touch fish, but doesn’t mind french fries cooked after fish. . . she has a very sensitive and discriminating palate and is the best at naming spices and herbs used in cooking.