One of the causes of device damage in 1:1 programs is often simple neglect by students. If your students don't think that they devices are necessary for all of their classes, they will leave them behind when changing classrooms, put them in lockers, or leave them laying on a cafeteria table. Make bringing their laptops or iPads to every class a requirement, not an option.
I saw this first-hand when my school first rolled-out a 1:1 netbook program. Some teachers didn't make using the netbooks important in their classrooms. In fact, some didn't have students using them at all. In my classroom they were a priority and students knew that they had to have them with them for every class meeting. At the end of my classes I would often see a netbook or two left behind. When I later asked those students why they left them behind they would say things like, "I have Mrs. X's class next, we never use them there."