I don't know that we can really answer your question about how long a bottle of oil will last, only because there are so many setting options it will really depend on how you choose to use it. With all these variations it would never be the same for anyone. You can use a 10ml bottle of oil and not fill it because it is a good way to also create mixtures as well. Yes the machine will stop when the oil is empty.
• Timer setting: 30/60/120 minutes
• Mist Volume Setting: High/Medium/Low
• Mist Interval Setting: 5/10/30/60 seconds
The Smiley Daisy Team