Thank you Suzie for your photos.I would like to start by saying that it is not about the best filler or the longest filler but mostly about the proper filler, properly injected. You will need more than 1 ml to correct the volume loss but once you achieve the result you were hoping for, you will just need to maintain in with very little touch up every 6-12 months.The duration of fillers varies from patient to patient and usually depends on factors like type of filler, amount used, area injected and the metabolism.Based on your photos, there is a significant volume loss around your mouth causing the lines to show. In my opinion to achieve a balanced look, it is advised to have filler injected into the lips ( both upper and lower, lip lines and around the mouth) I would utilize the combination of fillers like Restylane Silk, Restylane Kysse and Restylane Refyne . I suggest spacing the injections into 2-3 sessions to allow for easier healing time.The most of the treatment depends on the skills of the injector and the type and the amount of product to be used. Your concern requires a highly skilled injector to correct. The actual number of syringes to be used will vary based on the comfort level of the injector and your budget.Have a beautiful day and good luck in this journey. Dr.Anna Avaliani, NYC