Fox/cat eye thread lift after threads dissolve, how long does it generally take?

I love the look the fox eye thread lift gives. I was told the results last around 1.5 - 2 years, is this true? Though my main question is what is the skin like once the threads have dissolved? Does it leave skin saggy looking? Once they have dissolved would the eye area look more tired and saggy than before the procedure due to the skin being slightly stretched?