All purchase decisions have 4 steps:
(your sales window)
Motivation - First, you have a reason to buy something.
Investigation - You then look at the options you have to choose from.
Evaluation - Determine which is the best option.
Selection - Finally, you choose one and make the purchase.
This process can be considered the sales window – a window that opens when there is some motivation and closes when the purchase is made. Making contact with the potential customer in this window is a high probability sales call. Outside the window is a low probability sales call.