IT managers know application migration projects require time and effort, but even the savviest IT project manager might not be aware of the costs involved.

That is according to research recently published by mValent, a maker of automated application configuration management software. The company interviewed 10 of its Fortune 500 customers to learn what it takes to complete complex application migration projects and it seems it takes more than most anticipate. It could cause many to wonder if upgrading is worth the effort.

"Key reasons to upgrade include avoidance of compliance and technical risks, business benefits and improved technology," writes Paul Hamerman, vice president and principal analyst at Forrester Research, in a report. "Factors deterring and delaying upgrades include upgrade project costs, customizations, and business cycles and release maturity."

MValent discovered what it calls the "most common and significant hidden costs of this time-consuming, costly and error-prone IT undertaking when looking deeper into the efforts of its customers -- "two banks, three insurance companies, two retailers, a telecom company, a media company and a publisher" to be exact.

To start, the customer interviews revealed that the average migration project takes more than 20 "man-weeks" and costs on average $72,000 for labor. On top of that, total IT "direct-headcount" costs involved with application migration projects fall in the range of $500,000 and $800,000.

Aside from costs, customers also indicated challenges involved with migrating applications. Among the issues they face are high rates of change among applications in pre-production phases, mValent reports. According to the companies interviewed, such rates of change "contribute to system instability and extend troubleshooting efforts which result in scheduling delays."

Customers also noted that projects consume more costs and effort because they require more application instances to support a new implementation. And inconsistencies in "environmental variables" also contribute to project delays, mValent's research found. Configuration settings out of sync though out the development, QA and other pre-production phases wreak havoc on projects and cause even more delays. "Extensive analysis that wastes hours and days of IT staff time is required to diagnose and remediate the configuration setting differences that cause this issue," mValent wrote in a press release.

Denise Dubie is senior editor with Network World.