You probably don't need this if you have an SSD. However, if you have that and many regular drives and sometimes experience a slowdown which disappears when you do a manual defrag, then this might help.
Run Task Scheduler, then go to the Microsoft - Windows - Defrag folder. You'll see a ScheduledDefrag entry if you set a schedule in the Defrag program.
The problem is that defrag will usually run if there's nothing else running. If you have some software that does, then it will think that the system isn't busy and thus will not defrag.
To fix that, create a new task in the same folder and copy the settings of the one made by Windows, making sure that you have the ff. in each tab setting:
General - change the user to system, check "run with the highest privileges", and configure for Windows 10
Triggers - set the schedule that you want
Actions - run the program
%windir%\system32\defrag.exe
with the ff. arguments:
-c -h -o -$
Conditions - uncheck everything except for power if you're using a laptop
The system will defrag one disk at a time during the schedule given. Any SSDs will only be trimmed.
You can right-click and run the task to see if it works. Run the defrag program and you'll see that it is defragmenting one drive at a time.
You can also right-click and disable the task if you wish.
