How Long Does the Thread Lift Last?

14% is the satisfaction rate on this website from threadlifts, the lowest of any recorded category.
Comments from patients cover the gamut, from it didn't work, it didn't work long enough, facial distortion, extruding hooks, chronic pain, palpable lumps, etc. In our practice, we remove suture material from threadlifts on a weekly basis, usually while performing the facelift that patients needed initially.
Some patients do report seeing a benefit for a year, some for up to a year and a half. Some note immediate distortion and no results beyond a few months.
Why don't threadlifts accomplish the same as a facelift if they are pulling on the same tissues?
Strings placed through the tissues without any undermining tend to pull through the tissues. They do not hold up the way that undermined and fixated tissues do (i.e. during a facelift). An experienced facelift surgeon will require 20-40 sutures, placed directly in the deep tissues alone, to hold up the layer until it heals in a higher (and lifted) position. Strings are at a disadvantage because tissues are not undermined and only a few sutures are placed.
But this information is nothing new.
Patients should go into procedures with their eyes open to what the likely results are. Stringlifts do not produce facelift results.

With a very experienced provider and the right patient, a good thread lift can last 6-12 months. The dissolvable sutures used for this procedure trigger the body to produce more collagen, which extends and enhances the results of the procedure. In my office, we also frequently combine this procedure with treatments like RF microneedling or laser resurfacing to further prolong the results. I recommend working with an experienced, board-certified facial plastic surgeon who can customize your treatment plan to ensure you get the most satisfying and durable results possible.

This is an excellent question.
The Instalift is an excellent procedure to re-contour the face, lifting deeper layers of the skin for a more youthful appearance.  You see immediate results and there is no downtime. It is an option for people who want a lift without undergoing surgery.
Over time the sutures are naturally absorbed by your body while stimulating production of collagen to aid healthy renewal of your skin to produce natural-looking long lasting results.  Patients generally see improvements continuing over 1-2 years as collagen is remodelled.
It does not provide as dramatic and permanent results as a surgical face lift and a surgical neck lift.  However, some people do not want to undergo surgery and prefer the Instalift option.
If you would like to learn more about the procedure I recommend an in person consultation with a board certified facial plastic surgeon or dermatologist with cosmetic training.