I'd say it depends at least partly on the condition of the water in which you soak at the dive site. How long has it been there? How much gear has been thrown into it already?
In
any case, there's a bit more that needs to be done besides just soaking. Everything needs to be swished around to make sure it's properly rinsed. Particularly your second stages, to make sure rinse water gets all through them (careful not to depress the purge buttons!)... there should ideally be a separate tub with fresh(er) water for regulators and camera equipment.
And your BC will definitely require several rinsings
inside the bladder (water hose through the inflator hose), to get all the salt water out that will seep into there -- sometimes significant amounts.
Still, I'd throw everything into the tub when you get home. You know the condition fo the water there.
Of course, if you're on a dive trip, gear can go a week or two without any more cleaning than that. But then it'd definitely be into the tub at home.
And, oh... "pristine" is such a funny word when applied to dive gear that's being used...
--Marek