To manage the issue of underestimating costs in project management, consider the following best practices:

1. **Detailed Cost Estimation**: Develop detailed estimates based on historical data, expert judgment, and thorough analysis of all project components.
2. **Use of Contingency Reserves**: Allocate a contingency reserve for unexpected expenses to provide a buffer against unforeseen costs.
3. **Regular Review and Update**: Continuously monitor and update cost estimates throughout the project lifecycle to reflect any changes in scope or other variables.