I will replace a hdd when the ssd comes in a usb case so I can first boot from the ssd. It should have a Linux OS which would first clone the hdd. Than I would swap the hdd with the ssd. After booting again my computer should be exactly the same as it was before the ssd. There are clone programs that will not clone a larger hdd to a smaller ssd. Since ssd have usually less memory, it is hard to clone a hdd to them. After upgrading to a ssd, I should have a faster computer and a external hdd to store a lot of pictures and videos.