Hi, SassiGirl. Very important questions regarding BBLs! There is absolutley the potential that a BBL, or more accurately the transferred grafted fat, may last forever. And that fat, if well-incorporated in its new home, will expand and shrink with weight gain and weight loss. However, it is also possible for the fat to gradually atrophy or fade away. And it is also possible that the fat transferred does not "take" at the time of surgery, or that there may be a loss of the transferred fat after surgery due to pressure or trauma, poor circulation or infection. Whether one does a BBL, or simply has liposuction, it is important to try to maintain one's weight, as it is common for areas not treated with liposuction to accumulate the new and expanded fatty deposits with weight gain. Weight fluctuations can reek havoc on the skin itself, further damaging the skin elasticity. Good luck if you do decide to pursue a BBL. For many, a BBL and resultant liposculpture can be a very satisfying procedure, improving one's overall contour, enhancing the buttock contour and volume, and often i proving the overall appearance of the buttock skin. I strongly encourage you to seek an experienced and well-trained plastic surgeon -- determination of appropriate candidacy, good design and execution of the procedure, and diligent, knowledgeable aftercare all have a strong impact on results.