It is always important to know how you'll keep track of data during your research, but it's also becoming more common that your research funder requires you include your management plan in your grant proposal.
Federal agencies with large research budgets require that grantees make the results of their research publicly accessible.
For example, the National Science Foundation's Data Sharing Policy states:
Investigators are expected to share with other researchers, at no more than incremental cost and within a reasonable time, the primary data, samples, physical collections and other supporting materials created or gathered in the course of work under NSF grants. Grantees are expected to encourage and facilitate such sharing.
To meet this requirement, researchers applying for grants from the NSF, the NIH, and other federal agencies and grant funders with such requirements must submit a Data Management Plan, a supplementary document of no more than two pages. This document should describe the type of data to be collected, the data/metadata standards to be used, how the data will be made available to others as well as how it will be preserved long-term.
