Legacy software is usually good. That’s why almost every Fortune 100 company still runs tons of legacy software. Right?

Right. Legacy usually does mean "success". So many companies have legacy software because these old software do the job well. Because core business processes -- deep inside a company -- are not as prone to change as the more "visible" parts of a company. Existing software is also time-tested and usually free of major bugs. This legacy (goodness) must be cherished and preserved.

So why modernize at all?

We have seen here some real-life examples as to why software needs modernization. Here we articulate the main reasons why we need to modernize software.

DIFFICULTY: Older technologies are more difficult to maintain, and this is a key pain point for many legacy system owners.

COST: Difficulty translates into cost. Salaries of hard-to-find resources, time taken to make changes and licensing fees of older technologies -- all drive up the total cost of ownership (TCO). Software maintenance (defect repairs and enhancement) is the largest IT line item in America's larger corporations today. Capers Jones (the much acclaimed Chief Scientist Emeritus of Software Productivity Research) estimates: "Maintenance projects will potentially absorb almost 70% of the world’s software professionals during much of the 21st century."

LACK OF INTEGRATION: Legacy software typically does not integrate well with other IT systems.

COMPETITIVE PRESSURE: New technology can offer significant business advantage (e.g., sleek user interfaces, web services, etc.) and boost revenues as well as profitability.

NEW BUSINESS MODELS: New emerging business models often require more collaboration, new web services and greater interoperability -- which new technology can provide.

REGULATORY CHANGES: Sometimes changes beyond our control dictate changes that the old software might be ill-equipped to handle.

MERGERS & ACQUISITIONS create unforeseen need for integration, consolidation, bridging and interoperability that old software cannot handle.

INEFFICIENCY and the need for PRODUCTIVITY GAIN is another common reason why old software needs to be modernized.

BUSINESS AGILITY is sometimes a compelling need for the Top Management that is fighting for every inch of market share. Outmoded, archaic software prevents IT from responding quickly enough to the changes demanded by business.

The cost of "doing nothing" may appear to be less costly than modernizing, but usually there are significant costs associated with "doing nothing".