I always cover mine when its hauled... but at the slip, its difficult and
time-consuming to put on and take off a cover when I'm paying $200/month for
the 'convenience' of having it in the water. I want it to be convenient :)
So one of my main goals this winter is to fix all the leaks so I don't need
a cover when I'm at the slip. An air dryer and fan do a good job at
ventilating the moisture that does get in, but my hope is to have it so they
only have to fight condensation, not leaks. And it goes into an obsessive
thing for me: I just (irrationally, perhaps) feel that a boat shouldn't
leak.
I think I can also fight condensation by using small layers of insulation in
the worst spots.