are restored factory images perfect?

Hello all. In a nutshell, the question would be just as the title says. A couple of years ago, I purchased a gateway laptop that came with an i5 processor, a 500gb hard drive and windows 7 home premium. As soon as I took the computer out of the box, I created the factory image discs (3 dvds) and set them aside. I knew I would never use all 500gb in this particular computer, so I removed that hard drive and used it for archive storage and put in a much smaller hard drive. I used those factory image discs created from the original hdd to install windows 7 on my smaller hard drive and was happy to see that it also installs another factory image on the drive. all was dandy for a year or so. I've never used the factory dvds since, whenever I wanted to do a complete restore, I'd use the image already on the hdd from using those factory restore dvds. anyway, too many apparent glitches made me suspicious of the image on the hdd (probably unnecessarily but anyway), so I recently go and get my 2 year old burned factory image dvds only to find them with quite a few scratches on them. I go to run the dvds to do a complete factory restore and it tells me something along the lines of cannot communicate with device. I break out the toothpaste and chamois cloth and start buffing my dvd #1 and try again. I get further, in that it appears to start loading, and the progress bar starts progressing, but slowly and again I get some unremembered error message. I break out the toothpaste and chamois cloth again and retry. same deal. On the third toothpaste buff, I got it going, choppy and slow progress but I DO end up getting it to work. dvds #2 and #3 were ok. So windows was reinstalled, and was working fine as far as I can tell, but I am paranoid. Just how exact are factory images when re-installed from less than perfect media? Then an idea popped into my mind. I re-installed my original 500gb hard drive into the laptop and made 3 new recovery dvds. I again removed my 500gb hard drive and reinstalled the smaller drive. I wanted a perfect redo of the drive so I start using the 3 new recovery dvds and was blown away with just how fast these discs loaded and progressed. The dvd drive was humming along the entire time, progress bars were happily going and going etc. I distinctly remember the older scratched dvds winding up and down and all around.
Does windows allow for some garbage 0s and 1s in their image? Would having some garbage unreadable bits of info on a factory image stop windows from accepting it or should people rest assured knowing if it completed the restore task, it is perfect? I would imagine windows would check the image size, file count etc, but what if some 1s or 0s were not present or swapped due to scratches somehow reflecting the laser ahead or whatever? I'm a noob, take it easy on me!

The biggest risk you are taking is to rely on DVDs at all.

They are just less reliable all the way around for imaging purposes. Use your hard drive instead.

And even then, imaging is not a perfected technology. Usually, restored drives work fine. Sometimes the restoration process doesn't work as advertised. Plan for that to happen and know what you would do in that case.

thanks