Implementing an n-tiered architecture is costly. In the case of PatientKeeper, the ROI was obvious. In Thomson's case, an earlier conversion made pioneering wireless applications practical. However, for most organisations, the still-uncertain character of future wireless usage makes the ROI difficult to divine.

Forrester Senior Analyst Frank Prince says that because of the cost and complexity of enterprise-wide wireless, companies that can't calculate clear ROI are better off delaying an n-tiered implementation - maybe even for a couple of years. "Look at the problems people have just with enterprise-level CRM," he says. "And now we are going to define a standardised architecture and enforce it over a rapidly changing environment where we are not sure what will happen? The chances of getting it wrong are pretty good." Prince says that unless a CIO sees an overwhelming ROI, he is better off pursuing carefully controlled one-off applications while wireless matures and APIs improve.

That's the approach ArvinMeritor's Lipe is taking. "All we can do is make sure that we are ready when the time comes," he says. Currently his staff is implementing and evaluating low-cost, low-visibility projects like downloading intranet content to PDAs and a device-resident company phone directory. Neither application requires granting devices wireless access to corporate data, a step Lipe isn't willing to take until he understands the consequences better. Lipe is particularly leery of consultants and salespeople, the lions, tigers and bears (oh my!) of the wireless world. If you believe everything you hear from wireless vendors and rush in headfirst "you can find yourself in the position where you commit to a direction that you don't understand", he says.

In fact, just having an n-tiered architecture isn't a reason to extend applications to wireless devices. The wireless travel application Maritz's Hoffman describes is still at least two years away. "I wouldn't say we are scared, but we are approaching wireless with eyes wide open," he says. "We're making sure we do not get in it for the technology's sake. We need to make sure that we get the best return." There isn't yet a demand for wireless access to hosted services like travel booking, and Hoffman says he is going to hold out as long as he can. But he anticipates that in two years Maritz will have close to a dozen applications that will be accessed wirelessly and notes that they will likely replace the one-off applications he has now. In the meantime, he hopes APIs and standards will mature.

Eventually a company running wireless applications will need an n-tiered architecture to support them. "If you are gong to play the [wireless] game you have got to have a good, reliable, scalable back-end infrastructure," Hoffman says.

A CIO who fully understands the consequences of one-off wireless projects and sets realistic user expectations can certainly pursue those projects until an n-tiered implementation makes sense. But according to Hoffman, a CIO whose company becomes dependent on one-off wireless projects "risks making the same investment over again in just a couple of years".