How Long Should Swelling and Numbness Last After a Facelift?

I usually tell patients to expect about 10 days to two weeks for bruising to resolve after a facelift.  Many times it can be earlier, but I have heard so many patients say that "I am a good healer and will be less", and then it is still 10-14 days, that I want to be realistic and conservative.  I have also experimented with different aspects of the lift, including bigger, bulky dressings, tissue glue, and/or drains and none of them have appreciably improved healing time over other means. 
The swelling is typical, and begins to create a horizontal fullness to the face through the first week.  The second week the face looks more like patients expect, but can still be heavy or masculine along the jawline. By about a month, the face takes on a more natural, heart shape that showcases the strengths of a rejuvenating facelift.  But there is clearly swelling to the incisions, jawline, and neck to three months.  As swelling resolves, gravity draws it lower in the face.  So the jawline and neck take longer to resolve than the cheeks.

Swelling after a facelift is typically 2-3 weeks, but many patients can look good at 7-10 days. Numbness, however can last for several months. Most patients find the numbness quite tolerable and have very little discomfort post op. As the numbness resolves, some patients will experience a burning or itchy sensation, dude to nerve recovery. This is very normal and resolves over time.

This is a great question!
I would say generally swelling after a facelift begins to resolve after the first 2-3 weeks, however the time for complete resolution of swelling can vary from patient to patient. The majority of this occurs over the first month, however this process continues over the first few months after surgery meaning that the degree of improvement after surgery often gets better over time as things heal and swelling resolves. That being said, the swelling will typically resolve in different portions of the face at different times. For example, swelling of the jaw and neck can sometimes take longer to resolve due to its position and the effects of gravity.
Regarding the numbness, it is normal to have some numbness along the incision lines for several weeks to a couple months as there are cutaneous nerves in the skin that are disrupted as part of surgery.
Hope this helps!