If you Coolsculpted the same area 5 times, when would diminishing returns appear?

Each treatment would get the same reduction in fat, however the treatment area would be smaller due to previous treatments. However, Coolsculpting is not a weight loss procedure, rather it is for removing problem areas that cannot be removed with weight loss and diet / exercise alone. Keep in mind, for best results with Coolsculpting, a combination approach is needed. I recommend adding radiofrequency treatments like Vanquish, Venus Legacy, Exilis Ultra for skin tightening and with Z wave/Cellutone for skin smoothing. VASER with ThermiRF is a great alternative. See an expert. Best, Dr. Emer

I have also never treated someone 5 times in one area, but each time an area is treated with coolsculpting 20%-25% of the fat cells are reduced. an in person evaluation seems very important to continue further. 

Each time you do coolsculpting you should get a 20-25% reduction in the fat.  As the amount of fat lessens the total amount of fat treated will be smaller but it will still be 20-25% of the total.  Therefore with each treatment you will continue to get results. The results may not be as apparent as when treating a larger amount of fat.  Most patients will treat an area 1-2 times.  I've never had a patient need more than 2 treatments in one area, but there is no reason that it can not be done.. Liposuction would probably be a better option if an area needs to be treated 5 times,unless the patient does not want a surgical intervention.