Hi Prahlad,

There are probable as many ways to implement such a plan as there are designers to come up with them. The most important point I think you should take from this thread is the one voiced first by Michael, and reiterated by others, that this must be done with the full knowlege of the customer and agreed to in writing up front. To implement such a tactic covertly would certainly drive customers away.

But there is another reason to do this by agreement. It costs you extra to develop and implement this feature, and this should also be reflected in the price of the product. Presumably you've already developed your product without the "time bomb." The upgraded version should reasonably cost a bit more.

If a customer is paying in full up front, then you don't need to charge them for this additional functionality. Sell them the less expensive original version. Similarly, if a customer is established and trusted, they too do not need to pay for this added functionality. But to the customer who needs this feature, not only should they pay interest but they should also pay a bit higher price for the added functionality. And since they've agreed to it up front they are less likely to react badly to the process later.