It really depends on what you are looking at.
A refundable deposit is a liability, so it will not affect the P&L at all. Posting it to a customer deposit liability account hits the balance sheet. That shows you your liability. A report on that liability account can be customized to report on just one customer or all of them with deposits
You could also create a purchase order for the items you will need, or several PO's for that matter. While they are non posting and do not affect any financial statements, you could run a PO by customer report, customize it to report on just that customer or all of them and use it in conjunction with the balance sheet.
