Uninstall default apps

Given the always changing nature of the Fusion drive in keeping data blocks most frequently accessed on the SSD, apps that you never use should eventually be resident on the hard disk. Also, since the data management is by blocks of file-data, not complete files, even some blocks you don't access of apps you do access may be stored on the hard disk.

I know it is a popular impression here that ALL of the operating system resides on the SSD portion of the Fusion drive, but the study and reading I have done suggests otherwise ... that OS files are prioritized just like any other file and are moved as activity suggests. Of course, a new freshly loaded OS X system will initially have all of the OS files on the SSD until the systems learns your computing habits and starts to manage the drive mixture. And, OS files used constantly will always be on the SSD part of the Fusion drive.