At MSJ the cost of breakage was about 10% cost of the program. Which meant that more than 10% of the computers broke, but the cost to fix those came to be about 10%. Broken screens were the largest culprit. Out of 3 years I only had 2 that needed complete replacement due to mis-use, nothing stolen.
I did learn a few things.
1. Don't expect a sub-$300 device to last 4 years. At FHU we are going 1:1 next year and I plan to do a 2 year fair market value lease. This allows us to replace the devices every 2 years, and not have to pay the full cost of the device.
3. Loose hinges will destroy a device!!!!!! This started on Year 2, but the hinges started loosing. If the plastic mount breaks because the screws were loose the device is instantly turned into a parts machine.