Surgical time for a neck lift can vary greatly, depending on the surgeon's experience, concurrent technology use, and finally the degree of presenting face and neck laxity.
On the experience side, if a physician is combining a lateral facelift with a submental incision and platysmalplasty, expect the surgery to take anywhere from 1.5-3 hours, depending on the degree of work that needs to be done. Surgeon case volume can impact these surgery times. Be aware that the type of anesthesia used may also cause varied operative times.
On the technology side, newer devices like laser liposuction (which can reduce bleeding), absorbable barbed sutures which don't require knot tying, and products like PRP (platelet rich plasma) can reduce operative times. There are also a host of new cautery devices that when combined with facelifting can also reduce dissection times.
Finally, there are many different types of lifting techniques and combinations, and good surgeons tend to vary the approaches based on the degree of laxity and expressed patient expectations. For example, some people can get by with just lateral facelifting, or maybe combined lifting with just some type of liposuction. In these scenarios, times may be diminished. One thing to note however is that some people have features (heavier neck/jowls, thicker skin, etc) that may add more time to surgery. To this end it is important to have a frank discussion with your physician on what they think the times will be based on your features and your desired new look. Good luck.