Good question Missy. It depends what the botox is treating.
Most of the time, the botox helps to break a habit e.g. of frowning so once the habit has been minimised and the frown lines have faded, most have their botox on a preventive basis. For a botox virgin (first timer), it usually last 2-3 months. On average, botox last about 3-4 months and if have future treatments, it can last up to 6 months. So most people have botox 1-2 times a year. Hope that helps. Dr.Terry Loong Ethos Medical Director
http://www.ethosmedical.co.uk