DBA's and developers know the importance of having up to date statistics to ensure that query performance is optimal. Most of the time the statistics sampling percentage is left to the default.
To understand how the default is calculated see the following:
We don't change this, but there may be circumstances that will benefit from doing a FULLSCAN (especially if you have the window available to do this). For large or heavily used tables this could improve query performance, but remember that changing from the default will take longer and use more resources to update the statistics.
Read more here: