I had mine placed in May 1990 and have been using it since September of '90 - it's old enough to drink.I had a section patched in 2002, and had it ballooned twice prior to the patch. Since then have had no issues - knock wood. I get nervous talking about my lack of problems sometimes, my lack of hospitalizations, like I'm pitching a perfect game and I shouldn't talk about it but then I remember I'm not superstitious.My unit does an ultrasound of the fistula once a quarter - measures the size of the vein and the speed of the flow as well as looking for turbulence which could indicate a stenosis.