I have left mine down while in the water...but I do haul out once a month to clean the hull, change kicker oil, lube the pivot points on both engines and scrub the zincs. The motor is a 1997 and 20 yeas old next year..no corrosion inside or outside the leg. Obviously if the boat only comes out of the water once a year then barnacles would be an issue. By raising the leg and pulling the zincs out of the water they will crust over and will become less effective when back in the water. By leaving it down the leg is also not a big target for some poor boat handler to smack into and damaging or breaking it. For me it stays down