We have been running a perfect binder at Corley Printing Company in St. Louis for over 70 years. The amount of spoilage on a perfect binder (and only the binder for the sake of my comments here) are related to two key factors. First, if the job is a hot start or a cold start. A hot start can be defined as a job that is nearly identical to the job just off the machine. Spoilage will be lower than normal for a hot start. A cold start is, for example, coming in on Monday morning and starting up the binder, or a job with different paper and trim size than the one just completed. Next is the run quantity. You will need to figure a higher percentage of spoilage on low run quantities, and a lower percentage on long run work. We have a sliding percentage scale at Corley based on run quantity that allows for as much as 10% spoilage for 100 copy run (i.e. 10 books), and as low as 0.75% spoilage for binding jobs of 100,000 copies or more.

I just want to provide a little more clarification to Joe Piazza's excellent answer regarding spoilage: "One important factor to keep in mind is that spoilage rates are cumulative for each production process. For example, producing a perfect-bound book will likely include folding, binding and trimming. Each of these processes carries a rate of spoilage for both makeready and production procedures; these numbers must be added together to arrive at a total spoilage rate for a project. That's why spoilage quantities of 5% or more of the delivered quantity are not unusual." Practically this is correct and will yield good results most of the time. However, because each operation will likely be wasting 'good' product from the previous operation summing each the spoilage amount for each operation will leave you short at the end. If you have 3 operations with planned spoilage of 5% you should plan total spoilage of 16.6% . Of course, this is an exaggerated example but I have seen complex print projects (4 or 5 subsequent operations) come up short because spoilage was incorrectly calculated (via the sum method) necessitating very costly back to press runs. Here's an example: If you want 1,000 finished pieces and added 15% you would start with 1,150. Spoiling 5% at the first operation yields 1,093 pieces, spoiling 5% at the next operation yields 1,038 pieces and spoiling 5% at the last operation yields 985 pieces - 14 pieces short (or 14,000 short if you want 1MM finished pieces). - Bill