Thank you for the question.
Generally speaking, breast implants will "drop" into the pocket that was created during surgery. The rate of breast implant "settling" may depend on factors such as size of breast implant pocket dissected, tightness of the overlying skin/muscle layers, and size of breast implant utilized. Normally, it takes about 3-6 months (for some patients longer) to see the final result.
Similarly, it takes a few months for the breasts to "soften" in most cases. Most of my patients tell me that their breast implants feel "part of them" somewhere between 3 to 6 months after surgery was performed.
Many of my patients report that as the swelling around the breast implants (for example, in the sternal area) decreases, they feel that their breasts appear more projecting. Also, in my opinion, the "drop and fluff” phenomenon does hold some validity; as breast implants “settle”, many patients feel that their breasts actually look larger.
There is definitely a physiologic and "psychological" (body image) adaptation process that occurs, at differing rates for every patient, for patients who undergo any type of aesthetic surgery, including breast augmentation surgery.