I don't trust any backup facility that operates while the OS is live.
The only thing I trust is my old copy of Norton Ghost I think version 10 was the last version that you could install on a floppy. You then boot the floppy with a version of DOS and run the ghost software while the boot drive is totally inert.
I then take an image of the entire boot drive and then if I ever want to go back to the identical drive I can restore the image drive and I will have the identical software that I had the instant I took the disk image.
There is nothing that operates while the OS is alive that can make the same claim. There are always extra tracks left in the registry and there are always a minimal set of files that are "locked" by the OS and therefore inaccessible for backup.
It's the only method of backup that I trust and I use it before I install any new piece of software because uninstall never truly works and if there's an undesirable side effect of the install the only way to truly get rid of all traces of the install is to go back to the disk image.