As above, main box lives in the car, no point having to wash off EVERYTHING when you get home. No matter how careful you are the salt water gets everywhere.
I've got a Leeda tackle box, it fits everything I need to make up traces/rig etc. these traces then go into a rig wallet along with a few swivels/quick links and the like.
All I take on board is a flare tub that has the leads in, i then chuck in the rig wallet, a couple of reels, pliers, T-bar and digi scales. Its so easy just to have the one little tub rather than a big box.
Top tip... In my rig wallet I carry a few ziplock bags, once a trace/tackle has been used I stick it in a ziplock then wash it at home, this way nothing goes rusty.