Its well understood by IT professionals that change is the enemy of stability, so world-wide practice is that status quo is good. The poster I quoted didn't quote any good reason for those tasks, or the timing of them so unless you have inside knowledge you can't really claim that there was beneficial context, that is just hopeful supposition on your part.
Deleting history? Well only if you don't need it again.
Deleting problem cache? When did he say that those cache files had caused problems? Of course troubleshoot problems but randomly deleting cache files? No, that makes no sense and will eventually do more harm than good.
Of course "change is the enemy of stability", but some change is beneficial and some is even necessary. (Of course, every now and then we humans mess up and delete something important! Always distressing but it happens!) Deleting caches should be done carefully, but sometimes they do become corrupted and cause problems. As for deleting history, I generally like to do so on a fairly regular basis. And, I like the fact that Yosemite has different temporal options for doing so. But, that does not mean that someone should do so as soon as he or she has been to a site. If someone feel's that necessity, s(he) should use Private Browsing. As far as I'm concerned, the most important thing, be you an IT person or just a Mac user, is knowledge. And, that comes with study, experimentation, and even real mess ups!
