Final answer:
Butter-flavored oil can last for several months to a year when stored properly.
Step-by-step explanation:
The length of time butter-flavored oil can last once prepped in a bottle depends on several factors, such as the storage conditions and the specific brand and type of oil used. Generally, butter-flavored oil can last for several months to a year if stored properly in a cool, dry place away from direct sunlight. However, it is always recommended to check the expiration date on the bottle and use it within the specified timeframe for the best quality.