Thank you for your very good question. Since Latisse has not been around for an extended period of time, it is not known how to use it after the initially 16 weeks that were shown in the study. Eyelash growth can continue after several months of constant use with this product. Sometimes the growth gets to be too long for patients, where the eyelashes are now hitting their sunglasses or eyeglasses. At that point, it would be wise to back off on the use of the Latisse to twice a week and test how that does for you, but consult with your prescribing doctor for his/her recommendations. You can always go up or down from there on applications depending on how your maintenance is holding up. Eyelashes, like hair, have a defined life cyle of growth, maturity and then they fall out. Each eyelash is on a slightly different schedule and that is why if you stop the Latisse, it takes up to 3-4 months to have the lashes completely return to their original length and thickness. Hope this helps, Kent V. Hasen, M.D.