Microsoft on Tuesday disclosed plans to extend the technical support it provides for all of its development and business products to a minimum of 10 years, giving customers an additional three years to keep using its software before technical support runs out.

The change means companies can use many Microsoft products longer without the risks of running unsupported software or the costly alternative of signing a custom support contract. Among the products covered by the extended warranty are Windows 2000, Windows XP, and SQL Server 2000.

Under a support life-cycle policy introduced in 2002, Microsoft has been providing software troubleshooting and repairs for five years on most products, followed by two years of extended help for an additional fee. But that so-called "five plus two" policy has proven insufficient for IT departments under budget pressure to keep their Windows PCs and servers in service longer. "We determined we needed to make some changes," says Peter Houston, senior director of servicing strategy with Microsoft. The change was disclosed at Microsoft's TechEd conference in San Diego.

Under the new "five plus five" policy, which goes into effect June 1, Microsoft will provide mainstream technical support for a minimum of five years, followed by five years of extended support. If it takes Microsoft more than five years between major product upgrades, the support window will be extended accordingly.

In addition, Microsoft will now support so-called service packs, which bundle security updates and other features for a given product, for two years. Under the older policy, service-pack support had been inconsistent, making it hard to customers to plan, Houston says.

One product not covered by the policy change is Windows NT 4.0. Support for NT 4.0, introduced in 1996, expires at the end of this year. Many businesses are racing to swap out the millions of PCs and servers still running the operating system, but Microsoft decided against extending NT 4.0's support because of the security vulnerabilities posed by the aging platform. "NT 4 has reached its point of architectural obsolescence," says Houston.

The five-plus-five support policy change is an acknowledgement that some companies are skipping entire releases of Microsoft products. For example, a company that deployed Microsoft's SQL Server 2000 database last year might not want to upgrade to SQL Server 2005 when it ships next year. In that scenario, the customer could wait for a subsequent version of SQL Server.

David Chacon, an IT manager with golf club manufacturer Ping, approves of Microsoft's policy change. Chacon says it can be hard to keep pace with Microsoft's constant product upgrades. "Having longer life cycles can be very advantageous," he says.