TCO: a sum of the parts
The first advice about calculating TCO is to keep things simple. Think only in terms of bottom-line impact -- or cost. Think tangibly, not intangibly! You can easily mislead yourself by thinking that intangible contributions -- like increased productivity -- are important. In this example, what really matters in the equation is what your staff actually does with the extra time!

There are 6 basic categories that contribute to annual mobile solution cost. Each must be considered and profiled in order to achieve a complete picture of your mobile solution investment:

• Handheld unit costs
• Mobile solution set-up and deployment costs
• IT services and repair depot costs
• Mobile solution software distribution and management costs
• Training costs
• Help desk costs

Handheld unit costs
Of course, the actual cost of the handheld devices is the first thing to consider. Handheld costs must be amortized over the expected lifetime of the device, a lifetime that can vary widely by application, industry, and an enterprise's philosophy toward adoption of the latest and greatest technology. A handheld's lifetime can be one year, at best, in harsh environments (e.g., a construction site) or as much as five years when the handheld rarely leaves the protected confides of a fine Italian leather briefcase.

The mobile solution environment also dictates the consideration of three other important factors: loss, breakage and theft rates. A highly mobile handheld runs a greater risk of being dropped, left behind at the latte shop, or cherry picked off the lunch table. Handheld durability factors heavily into the breakage rate. Often, one drop of the handheld can decommission it for a screen refit or replacement of the device entirely.

Depending on the application, loss/breakage/theft rates can annually account for 1% up to 10% of the deployed handhelds in the field. The cost of these replaced devices must be accounted for as an adjustment in the annual handheld unit cost assessment.

Finally, there are the handheld accessories (e.g., protective cases), peripherals (e.g., add-on memory and batteries, printer, barcode reader, folding keyboard, cameras), communication/data services (e.g., wireless email accounts, paging services, and voice services) and third party software application licenses to be considered. Such costs add substantially to the base device unit cost. The total add-on costs should be amortized over the expected lifetime of the handheld.

Mobile solution set-up and deployment costs
An enterprise mobile solution typically requires a modification to the central corporate infrastructure to accommodate fluid bi-directional data exchange between headquarters and the field. Upfront costs for the underlying solution framework -- synchronization servers, extra storage, synchronization depots and connectivity enhancements -- must be factored into the cost equation as an amortized mobile solution lifetime expense.