Computer Help and Support

A good reason to copy clone to new HDD is that, being newer, should be more stable (although these days, could be reverse...) thus less likely to crash.

As for keeping the clone itself on a 2nd drive: I'd keep it til I knew everything transferred correctly etc. Then, I would use the 2nd drive as a backup. But that's me, I tend to err on the side of caution.

ETA: hold on, just realized the clone is on a "flash" drive, so presumably a USB stick? If so, leave the old HDD as is, except I guess move it to other SATA slot. Then all old data is already "backed up" but not as an image (that needs software to read/restore) but just as it is now, except the drive will be renamed from "C:" Easy access to data (but not programs).