Once your doctor has determined it's okay for you to use Latisse, you'll be able to reorder the product as you wish. Very few people are advised not to use the product, but there are some conditions that need to be ruled out first, so that's why you can only get this item through a physician. There are a few ways to get the most out of the product container so it lasts considerably longer than is indicated on the packaging. Your doctor or the doctor's staff should demonstrate the correct application procedure and they'll probably show you the most efficient way to use it so you get the most useage. Just ask. You'll see the "final" results in 16 weeks, though most people see some growth at 8 weeks or sometimes earlier. You do need to continue use to keep the active phase system going. After the 16 weeks you can usually go into maintenance mode and use Latisse 3 or 4 nights a week. You'll discover what works for you fairly quickly. Latisse is based on a hair growth cycle enhancer. Basically this simply means that the lash hairs (and brows) will stay in the active growth phase longer than normal, so your lashes are longer and the density of the lash hairs increases (thus the increased fullness).