Apology if it was unclear. What i meant was:-
1) Do i need to buy a window installer disc for clean installation?
2) would it be prefer to have a disk imager like Acronis or Macrium Reflect?
I read that many preferred Acronis but the 2015 ver isn't that stable.
You do not need to buy a Windows disk for installation. If you needed one you can download an image and burn it to DVD or put on USB.
For the purposes of recovery you don't need anything else.
You can easily copy all your files to USB HDD with explorer or Windows backup.
If you want separate backups or images with the most flexibility and ease of use then you might be interested in another product however they are not always as easy as they may lead you to believe. The key to any of this is knowing the right steps to take in the situation. especially if you need to boot to a recovery disk because of changes with secure boot and UEFI bios products may have different requirements. YMMV.