I have a decent image of my O/S already if I want a quick-reinstall from a HDD failure/disaster.. IMO it's not as useful to have an o/s loaded down with programs, you'd be surprised what you can do without when recovering from a system crash (therefore regular incremental o/s recovery isn't as important.) Of course imporant data worth saving gets backed up immediately-- on dvd or blu ray, but havent' had much of that lately.. hence the weeks comment. Important info such as bookmarks, text files and whatnot can easily be backed up to flash drives or mirrored/synced to a tablet or smartphone..
* The way Windows O/S work, I'm of the old school that knows registry cleaners and program removal aren't as efficient as a fresher) install of an O/S.. Much like taking a haircut.. feels nicer to have a clean O/S and drive. (always good to have a "stock PC image that isn't overburdened with program installs). I haven't gotten close to filling my 1tb drive up.. I'll delete files around the 300gb free range.. 3+tb drives are all about warehousing data.. mainly media files. The important thing to know is after the reload, it's important to reinstall security updates, update antivirus/malware, update flash/java/a.reader, and any other media codec platforms.
The bulk of what consumers put on large hard drives are media files-- much of which probably comes from the internet. For that you only need a database of the files for recovery in the worst-case scenario. Backup of an O/S onto optical disc isnt' as useful (except in rare emergencies and for redundancy)I's betterr to be able to recover the image from an external HDD or flash drive-- less time consuming. It's rare that I'll have an issue with virii & root kits.. If the average person wants to avoid that they should stay away from google search.. seems to be picking up steam lately..