Last week, we discussed the fact that data center consolidation is a top priority for most IT managers. Application consolidation isn’t far behind.

Most companies we work with have more applications than they want - typically several hundred to several thousand. Many are legacy apps - programs more than 10 years old and either home-built or purchased from a vendor that is no longer in business or supporting the product.

I recently spoke to one IT manager who’s managing more than 5,000 applications (yes, that’s three zeros), and another who’s trying to whittle 600 applications to 60.

Why consolidate? Decreasing the number of vendors you deal with, and the number of licenses or home-built apps you manage, can reduce complexity. And replacing legacy apps could significantly lower your costs downstream. One company I’ve worked with still runs dozens of industry-specific programs that are more than 20 years old. Though the applications continue to work well, it’s getting more difficult to find technicians with the skills (and desire) to support them.

There are several ways to consolidate applications.

First, use a suite of products from a single vendor, such as Oracle or SAP. Relying on one vendor for all your needs in a particular area (say, customer relationship management) can ensure that your business processes are well aligned across applications. And using multiple modules from a single vendor can significantly reduce - though rarely eliminate - integration headaches.

But there are downsides. Replacing homegrown apps with a suite usually means sacrificing some functionality; suites don’t offer the depth of features that many best-of-breed vendors do. Smaller enterprises may have greater clout with smaller, best-of-breed vendors than with the “big guys” like Oracle and SAP. And consolidation can equal lock-in; once you settle on a handful of vendors and rip out everything else, it can be hard to go back.

Second, migrate to apps based on Web services, which can help minimize redundant functionality. Given that Web services frameworks permit the creation of homegrown applications that are standardized, easily supported, and spot-on when it comes to delivering the specific functionality required by lines of business, you may want to consider consolidating several archaic apps into a Web-services-based solution - and thereby make your life easier down the line.