I just had chin liposuction. how long do you think it will last?

Long time.: If you maitain your diet and weight it will last very long time barring your aging process.Skin will sag with age.

Forever: The fat you had removed will never return. The fat that remains behind can still increase in size if you gain weight, but that old fat is gone forever. Your skin however, will continue to age and you might want some sort of skin rejuvenation procedure down the road to maintain your youthful appearance. Be well.

For a very long time: Once the fat under the chin is removed, it should not come back. You would have to gain a substaintial amount of weight for it to return.

Depends on you: If you maintain a stable weight, it will last forever. If you gain a significant amount of weight, some fat may return there...But mostly you'll tend to gain weight in other areas.