Hi
No it is not removed unless there is a medical reason, if it were removed then I know the weight would then be put back on even though our minds are used to eating smaller meals.
I think that they last around 10-20 years and I am sure then they would just be replaced.
BYpass is however forever as one of your intestines is made quite a bit smaller to absorb less and your stomach is devided into two.
I have just added a website that I think explains it quite well :
Lap-Band vs. Gastric Bypass Surgery
good luck
x