Is there a possibility of mice in the units? Any time there's a roll-up door, the possibility is there. The only ones who can legitimately claim to be totally pest-free would be those with air-tight doors. It's possible for them to squeeze around a roll-up door where the track is -- how do they do that, anyway?

We have not had significant problems with mice and we have random cats who like to wander around in our lots, but plan for the possibility in any storage facility.

• Pack items of particular concerns in plastic bins
• NEVER store food. You won't want to eat it after being stored for a few months anyway, so throw it out before and not after!
• The best place for traps or poison is on the corners of the doorway -- it will be the first thing they'll see if they do manage to get in.