Agreed, which is why I create weekly backups of my most used OS's & monthly of those less used. I always keep the 1st backup taken of a new PC or install after updating & removing junk software, so that I'll always have a clean install to revert to, as well as keeping the last 2 taken.
Though I haven't accessed those in awhile, I still have my XP backups available, though will be destroyed once I install Linux Mint on the last one. Should I see or donate the computer, I'll include the OS reinstall media set.
More recently (last summer), I did use the in place repair install on an XP computer that wasn't mine & it was successful. However, there weren't any hardware changes, just some corrupt Windows files. Had read that was the best way to fix the issue, as I recall, on the "How to Geek" site.