My experience is never the same in each individual patient. I have seen patients die quickly and painlessly within one day. I have also seen patients linger in hospice for several months but generally die relatively painlessly. Some patients with very poor hearts and fluid retention, have a very difficult struggle with fluid retention and shortness of breath. Most of the studies that I have seen estimate that if someone has been on dialysis for at least 6 months and choose to stop, death occurs on average within 2-3 weeks. This mostly has to do with how much kidney function remains in their old native kidneys. It also depends on what other medical problems and chronic health status. Patients who are not able to perform their own activities of daily living and are elderly do not do very well with dialysis care and do not live very long if stopping dialysis.
You can review a web page on our web site that discusses this issue at: https://www.kidney.org/atoz/content/dialysisstop