I only have one large shelf unit (in the garage) where I keep my most used items, which means the unit boxes that a)are coming up soon or b)are just finished (because I inevitably find bits and pieces of unit materials for awhile after I finish a unit). The rest of my boxes I keep in a loft storage space in the garage, so I have to rotate them from time to time.
I also keep a box in the garage labeled "Things to File in Teachers Boxes" for those times I find something (or purchase something) that belongs in a unit box up in the garage storage area so I don't have to keep going up to those boxes. When the "Things to File" box gets full, it's time to go to the off-season boxes and put everything away.
Down came Bunnies and Baskets and Signs of Spring and Pets and Farms.
Here are a few of the new Theme Box Labels:
You can purchase them here and here, at only $2.00 for the set.