Mine lasted nearly 5 years. In reality, I think it was less than that but I didn't get very good ongoing care from my surgery for over 4 years. I was largely left to my own devices, with repeat prescriptions for prednisolone being signed and dished out like sweeties. Then a new GP joined the practice and she was shocked to find I was still on medication after four years, so she helped me to come off it, ordering monthly blood tests and follow up appointments. I finally came off the meds 3 months short of 5 years after diagnosis. I've not had a single twinge since.
Please shysal make sure your GP is on the ball with your treatment, and push for regular ESR and/or CRP blood tests to measure how the condition and treatment is progressing. I feel rather silly now that I allowed it to go on for so long.