According to Mohanty, establishing an SOA governance mechanism will define and establish the policies and procedures to manage ownership of services, streamline the mechanism for communicating about the services available, ensure reuse and measurement of design-time, run-time and change-time metrics. "This enables enterprises to proactively manage any cost overrun effectively and ensures that the SOA program is under control," he says.

Assuming you wish to plan the reuse efforts yourself, or that you wish to oversee your SOA architect with an inkling of knowledgeable authority, where should you begin?

Start with understanding the pros and cons of SOA overall. "Software design — not just SOA design — is always a trade-off of maintainability, performance, risk mitigation, and cost," explains Craig. "Reuse can reduce costs and add benefit because you are reusing tested, proven services instead of writing them multiple times. When you maintain them, you maintain them once, instead of repeatedly, which also reduces ongoing cost."

"On the negative side, it can engender risk of poor performance, especially in SOA designs where multiple services can 'find and bind' to a production system — a risk that can be mitigated by governance of the use of services," she says.

The next step is discovering which components make sense to reuse first. Keep in mind that it isn't necessary to do everything at once.

"We strongly advocate an incremental approach to SOA, and in fact that has been the dominant approach to adopting SOA," says Larry Fulton, senior analyst at Forrester Research. "Like anything else new, there are startup and training costs, but we've seen organizations achieve better flexibility, time-to-market and service re-use with only a handful of services, in twelve to eighteen months' time."

Obviously, even a baby step must be taken in one direction or another. So, which foot goes where?

The basic line-up of components for reuse, according to Sandra Rogers, director of SOA, Web Services, and Integration Research at IDC, is "infrastructure and technology services, information or data services, and then common-place functional routines."

Rogers says many organizations start with infrastructure or technology services, such as security, monitoring, and auditing to immediately help free up business application programmers to address more added value activities. This can also help ensure consistency to enterprise protocols and create an environment that is much more efficient in addressing changes to these routines. "As a side value, it helps reinforce more reuse of services in general by supporting a more secure and governed environment," she says.