The bottom line on Opportunistic Reuse varies considerably, depending on how big the reuse opportunity is. Small amounts of Opportunistic Reuse will produce small savings. Large amounts of reuse could probably produce effort savings in the range of from 20 to 25 percent over the life of an entire project, assuming that large amounts of code and design can be reused and that there is some staff continuity between the new program and the one being salvaged.

Planned Reuse is not a short-term practice, but the long-term payoff makes it an appealing strategy. In one study of software process improvement in 13 organizations, some organizations demonstrated much greater productivity gains than others (Herbsleb et al. 1994). One company improved its productivity by 58 percent per year for 4 years. Another cut its time-to-market by 23 percent per year for 6 years—that's a total reduction of 79 percent. The authors of the study attributed both of these extraordinary gains to reuse programs.

Because of the organizational and quality-assurance challenges, it can take a reuse program 2 years to develop any components that are truly reusable (Jones 1994). But productivity with significant reuse can exceed 35 function points per staff month compared to a national average of about 5 function points per staff month. Because use of reusable components completely eliminates design and construction and reduces the amount of quality assurance needed for those components, a successful reuse program is by far the most effective productivity practice available (Jones 1994).