Individual response will vary when treating the lines around the eyes with Botox or Dysport. However, the average patient should expect a minimum of three months duration. If one is not achieving the minimum, they should discuss this with their practitioner inasmuch as technique and proper dosing is important when tailoring a treatment plan.
The benefits of consistent Botox & Dysport treatments are that one should be able to sustain results and require less treatments or less dosing as time goes on.
In addition to addressing "crow's feet", make certain to discuss the option of a "lateral brow lift" which adds increased benefits for eye rejuvenation.