Even if the storage facility takes measures to control pests, you want to be sure that your unit and possessions are free of rodents and insects. These critters can ruin the contents of a storage unit faster than can be imagined.
The first step to insuring that you don't encounter problems of this sort is to never store food in a storage unit! Don't keep food in a boat or RV that is in storage either. You can be guaranteed that bugs and mice are looking for things to eat and will find a way to get it if it's in your unit
Next, keep your unit clean and tidy. Sweep the floor once in awhile so there is little or no nesting material or debris that might otherwise interest pests. Sweeping will help break up cobwebs and chase off other bugs considering taking up residence. If items in the unit are stacked neatly, it's easier to spot a problem while it's still small.
Last but not least, place packets of mouse poison and roach traps in your unit or RV. I'm not one to use a lot of pesticides and poisons, but this is the best way to limit damage; especially if you are storing things for more than a couple of months. Remember to change the bug traps out after they expire. These don't stay potent forever.