During the 6 months period the balloon is implanted, you will benefit from a follow up :

Medical
A control by your gastroenterologist at least every 2 months
Radiography or ultrasonography of the abdomen to check the position of the balloon..
  
Nutritional
With a dietetics consulting every month..
Your physical activity is evaluated and adapted.
 
Psychological With a possibility to participate to groups of patients discussion.

The maximum placement period for the balloon is 6 months.

If your doctor recommends a placement period of more than 6 months, it might then be necessary to replace a new balloon, because,  the acid contents of the stomach deteriorates the material of which the balloon is made over time. It could deflate and then migrate into the intestine. Most often, the balloon is evacuated naturally, but there is a risk of bowel obstruction if the balloon gets stuck in the intestine.

After the removal of the balloon, the follow-up must be maintained to avoid the resumption of weight and to continue to lose weight if the loss was not sufficient.