In most cases, e-juices are available in 10 ml bottles, with varying strengths. If you buy a 500 mg oil and opt for taking 15 mg per day, the bottle will last for one month. And if you buy a 1000 mg bottle, it will last for over two months. Be careful with storing the vape oil since high temperatures can negatively influence the product.
Regarding the duration of the effect, it usually takes only 10-15 minutes for CBD to enter your bloodstream, and the effect lasts for approximately 2 hours.