More boats than you think sit in salt water all season for years and last decades. The exhaust needs to be replaced every five years with constant salt water use. The bellows will last about the same.
The drive should always be in the down position else it stresses then and results in premature failure. Also the trim zinc may be out of the water if up and the drive will not be protected.
Not in salt you have to use zinc or aluminum anodes.
1997 2400 SCR
5.7 Vortec / Bravo 2