I think it's a combination of doing your homework on the customers credit record and generally getting a handle on the risk involved plus fine tuning of your terms and conditions to minimise your exposure and finally establishing payment terms that you can work with ie what % deposit etc.

There are many companies that will tell you they don't give deposits or they don't 'work that way' but believe me there's always lattitude for them to pay a deposit if they have no option. We are maintenance and repair agents for specific machine manufacturers and distributors and in many cases we're the only option the customer has for service and off the shelf spares without flying somebody in. We often have customers who will dig their heels in about paying a deposit of even COD for spares but they almost invariably 'make a plan' when they realise there's few other options.