The chance that the average gamer customer will come in to pick up an item you've promised to order for them: about 50%.
The chance that a regular customer, someone you know by name with a track record, will come in to pick up that item: about 75%.
The chance that a customer will come in and pick up a special order placed with money down: about 98%.
That the last number is not 100% tells you there is no certainty that customers will ever return to pick something up, even after they've paid for it. That's why we require payment in advance for special orders. If someone who pays for an item won't come pick it up, what's the incentive for those who don't?
For some, it slips their mind. I think a lot of the muggle customers just go to the next store to look for that item, as they have no relationship with us. I think many had no intention of returning, despite my promise to get their game and their promise to come back.
Purchasing is a zero-sum game. There is X amount of purchasing money for the whole store. It fluctuates based on sales or releases, but the total stays the same. If I buy a new Warhammer model, for example, it means I'm taking money away from something else I could have re-ordered or brought in as a new product. If I have to sit on some muggle special order Hasbro board game, that means I lost the opportunity to sell something useful and make money. In business terms, it would be called the opportunity cost.
The cost of passing up the next best choice when making a decision. For example, if an asset such as capital is used for one purpose, the opportunity cost is the value of the next best purpose the asset could have been used for.
For example, if I special order a $20 Hasborg board game and it sits on the shelf for a year, the opportunity cost in gross profit is theoretically $80. That's $20, times 4 turns, or sales (money used for a solid game I could have bought). Trust the muggle and you have a 66% chance of losing $80 in gross sales on a $20 game! It's all theoretical, but after a while, these theories become general principles in your business.
Not to meander any further, but this also reinforces the concept that the money in retail is made in the purchasing of goods, not their selling.