I use Macrium as the daily scheduled C drive image backup.
Every night at 2 AM
Every Sunday at 3AM, to another PC.
C drive of 125GB used space takes about 14-15 minutes to complete, and results in a file size of ~94GB.
The only fiddly thing with the Free version is the default settings.
Default is set to a Full, and then Differentials, keep for some weeks.
If you want to schedule something different, you first have to modify the Default settings, and then set up a schedule.
I have mine set to do a Full every night.