To schedule Disk Defragmentation on Windows 11/10 in order to improve your computer's performance, use the steps mentioned here.

Windows 8.1 Open the Start menu by clicking on the Windows icon on the taskbar, and type defrag in the search bar. Select Defragment and Optimize Drives. Select the disk drive you want to optimize.

The Vista Rewired weblog details how to significantly speed up your Windows hard drive defragment (over 10 times faster, according to the post).

In fact, Windows does sometimes defragment SSDs—on purpose. Scott Hanselman explains on his blog how Windows treats SSDs after digging into the topic with developers on the Windows storage team.

Windows 7 automatically defragments your primary hard drive in a process that runs quietly in the background. However, if you'd like to have all new drives you plug in be defragmented as well, it ...