Jon is correct - it varies, albeit the longevity of some aluminum
masts can mirror the life of a boat. It will, however, depend upon a number of factors including the original construction, whether it has been sailed in fresh or salt water
, whether the rig has been properly tuned, whether it has a tendancy to pump in certain conditions, whether it has undergone regular bending due to adjustable back stays, whether s/s machine screws/hardware have been properly bedded/isolated, whether a paint
finish has been allowed to bubble and hold in moisture against the aluminum
, whether there is proper drainage at the mast step,
The standing rigging
, including not only stays and shrouds but tangs, and also the internal blocks in the mast and boom will, however, need replacement over time.