When is it time to image my C drive?

System works good in Win 10... I've done all the right things in cleaning out old OS, hardly anything in cleanup to fix, have docs and most files linked to the D drive, mostly just Win 10 and program files, program data on the drive itself. It's showing 19Gb free of 223Gb on my SSD.

I did buy a 500Gb drive so it's ready to go... I just get the heebie jeebies thinking about imaging the drive to a new one and swapping them out. When would you install the new one?

a. Stop being a wimp and get it over with.
b. I'd run it until you get to about XXGb free. (insert number here)
c. Run it till it starts giving you errors or starts smoking.

Do it now. You will want the extra free space available when the Anniversary update hits on August 2.

You say you have a D: drive, assuming 2nd hard drive. Save an image file using Macrium Reflect free of the entire current SSD to the second hard drive. Make yourself a bootable Macrium Reflect rescue flash drive/DVD or Kyhi's recovery drive. Make sure your computer can boot from the rescue/recovery drive. Swap out the SSDs, boot from the rescue/recovery drive. Restore the image stored on the second hard drive to the new SSD.

If for some reason it doesn't boot, use the rescue/recovery drive and in Macrium under the restore menu is a utility to fix Windows boot problems that should get you easily rolling again.

If the entire world goes to crap - you can always just put the original SSD back in.