Here's the repair tag we use, by stapling to the handlebar. They are color coded, based on destination: reserved for shop sales or reserved for school programs/earn-a-bike. We keep an inventory in Google spreadsheet that lists the data on the tag. At the end of the year, it becomes easy to sort the column and count what bikes were sold, what bikes were sent to schools, or donated to other causes and # de-manufactured. Theoretically, you could keep the hard copies and count, but some always end up lost - so it's not a great system unless there are fewer people involved who are equally committed to the inventory system.

We start the new year's inventory with all the bikes that had no destination in the prior year. 

In our two stores, we use Light Speed, which tracks and prints out the repairs done.

Karen