When two people each do something that could have been done only once, time has been wasted.
Try to consolidate effort.
- The whole concept of education (saving civilizations from the labors of civilizations past).
When NOT to consolidate effort
Often is is not known what the best way to do something is. In this case, it is often beneficial to allow multiple individuals or groups to pursue their own ideas. Intermediate progress should be shared when possible, however.
The free market; competition
The free market allows multiple companies to solve the same problem at the same time. However, there are strong incentives for these competitors NOT to share intermediate progress. This is vast duplication of effort. However, it is necessary to allow the free market's mechanism of rewarding people who make progress.
Each student in elementary school solves the same arithmetic problems that thousands of other students have already solved. This is because there are benefits to a student solving an arithmetics problem beyond the possestion of the numerical answer.
Sometimes learning is a tangential benefit. Many software programmers end up learning how to code a few key algorithms. It may be better to implement these algorithms once and never have anyone look at them again. However, recoding these algorithms is not an absolute waste of time; as a tangential benefit, programmers learn more about creating algorihtms.
Redundancy provides robustness to change. Because of capitalist competition, many teams of people at competiting companies learn to do the same task. This wastes effort, but one benfit is that if one of those teams gets into a tragic accident (or, more prosaically, if key people in one team switch to different careers), there are still others available in the industry who know how to complete the task.
See also ConsolidateInformation.