Ya as a lot of BAVs last a lifetime without needing repair or replacement I'd say it probably varies quite a lot. Obviously I'm a tad biased as I had a repair earlier this yr, but my valve wasn't the cause of my surgery. That was the nice fat aneurysm. The valve had trace leakage and no stenosis but while he had the wheels off he fixed the leak. He knows a bit more than I do about the subject so I accept his optimism when he tells me as far as the leaking he thinks my valve is good for life but obviously as far as calcification and stenosis nobody has a crystal ball.