Just to be accurate, I should tell you that I prefer direct excision of the neck fatty tissue rather than liposuction. The skin is already elevated for the facelift and necklift, so I have direct visible access to the fatty layers, and can remove it much more thoroughly , evenly, and with much better hemostasis (control of bleeding points) than by "blind" liposuction. This technique is so much better than lipo (in this area) that I routinely use the direct excision method even when NOT doing a facelift or necklift and only removing fat under the chin (for a younger patient who does not need a facelift). For example of this see my photos on this site, or click on the link below for more information (cases 1 and 3 in the chin augmentation section, and case 3 in the facelift section are patients of mine that are applicable to this discussion).
Since I include a necklift as part of my SMAS facelift, as well as the fat excision under the chin, I can tell you that surgical time runs very consistently at around 3 hours, skin incision to last skin suture. You must realize that there is additional time for surgical prepping and draping with sterile towels after anesthesia is induced before the operation begins, as well as hair wash and bandaging after surgery is complete, so I would schedule 3 1/2 hours of anesthesia time. Men have slightly larger faces, and usually quite a bit more bleeding that needs to be carefully controlled, so I schedule 4 hours anesthesia time for the 3 1/2 hour surgical time for a male facelift patient.
Although exact surgical time varies with each patient, with years of experience and lots of these surgeries comes a fairly consistent time factor. As I tell my patients, "I don't look at the clock; I don't rush; and I don't dawdle--I just do my best to do good work!" And that takes a similar time for the vast majority of patients!