No producer can predict with absolute accuracy the number of items they are going to sell. If you produce too many items that you don't end up selling, you over

No producer can predict with absolute accuracy the number of items they are going to sell. If you produce too many items that you don't end up selling, you overspend on production costs. If you produce too few, you cut your revenue. Optimizing the balance between these two extremes is part of running a successful business.