I have a severe hernia and have to have a foley in my stoma all the time to bypass the hernia to let my urostomy drain properly. I use a FR16 Catheter with anywhere between 15 - 20 CC of sterile water to keep the catheter in. I change it weekly, or if it gets plugged up from mucus sooner, I then change it. I've had my hernia repaired twice and it just keeps coming back. Due to the complexity of getting it fixed, I have chosen to just use a foley for the remainder of my life.