Managing your research data makes it easier to share quality data and metadata. Other benefits include:
organization - managing your data makes it easier to work with;
time saving - having well organized data saves you time in the long run and allows for more time to be spent on analysis;
compliance - many funding agencies require researchers to make their data available
In summary, data management makes it possible to reproduce work, preserve work, and often times, data management is a part of being compliant with research funding agencies requirements for public data sharing.
Why would you choose to share your research data?
Data sharing can be informal, for example, posting data on a website, sending data via email upon request, or formal, for example, added to a data repository.