As anyone who has ever had a mouse in their home can attest, mice can do a tremendous amount of damage to household goods. Now try locking them in a room alone with your household goods for months with no interruptions. They can chew through boxes make nests out of clothes squeeze through tiny little openings, scale slick near vertical pathways. There does not need to be any food to draw mice in they will worm their way in just for the fun of shredding a first edition rare book or building tunnels through your new leather couch and love seat combination. The only household goods that are safe from these terminals are plastic toys.
So, what can you do if you need to store your household goods in a self storage facility for a period of time? You can box all of your goods in those plastic tubs you can buy at Walmart, even the most tenacious mouse is not likely to go through one of these. And even then the little rodent would only have access to one box of your goods while he starves to death now toothless and suffering. Make sure the storage unit facility your using has a mouse abatement program. Mouse abatement can work quite well but it really needs to be distributed across the whole facility to work well. Therefore; the programs that work are ones that can usually be seen by customers, like blocks of poison in every unit, or metal mousetraps on the edges of each building, or five gallon buckets which are used for traps at the ends of buildings. If you do not see the tale tell signs of a mouse abatement program then the self storage facility probably does not have one.
What other options do you have, a mouse proof facility, do these actually exist, yes, they do and the ones that are mouse proof are typically dust proof as well. In these types of units if you do not bring a mouse in with you when moving into the unit then the mouse can not get in. These units are usually based on the shipping containers that come over the ocean from china on a ship and the are sealed steel container with a weather, dust, mouse proof compression seal all around the door. When the door is closed it smashes down the weather proof seal around the edges using an 20 inch lever on the door latch when the door is closed correctly nothing is getting in or out of that storage unit until it is opened again
Of course there are those that say they are mouse proof but they are not take a look around the unit is there an gaps between one unit and the next big enough to slide 4 credit cards stacked up through. Even on the ceilings rafters are highways for mice and if storage facilities have them better yet have abatement program for mice.
So watch what you are doing and you really can avoid the storage unit floors.