After liposuction on legs, for how long do I have to drink extra fluids?

It is very important to stay hydrated after liposuction as you know.  Initially after surgery, your body will trap much of your extra fluid in the tissues in the form of swelling which is absolutely normal.  Over the course of the first couple weeks that swelling will begin to dissipate.  With respect to how long and how much you should drink, let common sense be your guide.  Everyone is different and it is greatly dependent upon how much liposuction was performed.  You should be able to urinate 4-6 times per day on average and sleep through the night.  If you are requiring more frequent trips to the restroom, then you may be overdoing it and can cut back.  Hope this helps and thanks for the question.

Good hydration is key after surgery. There is no one specific time to stop, but certainly for the first several weeks after surgery you should focus on keeping well hydrated.