We started with a lot of bins but soon realized that they were a waste of time and space. We have a few bins for items that are not used often and we have one for the hose and water filter to keep everything else dry. On the back side I have the things I need to connect the trailer and utilities as well as a few tools. On the front we have chairs, ez up, levelers, rugs etc that my wife can get to quickly and easily. When we had all bins we were always looking through them to find what we wanted and then we had empty bins under the trailer for the entire trip. Got tired of that in a hurry.
As others have said, go through the entire storage area once a year to remove things you do not use.