The issue with notes is when the solution changes because of an update. Using Google and grabbing recent solutions gets you updated answers if and when things change.
I try to find the balance between both of these options. I think it’s important to remember that just because someone wrote a blog post recently doesn’t mean it’s better. It also depends what you consider “core” knowledge, as an example I don’t need to google how to rebase anymore but I sure as heck do google something new about git every week.
Sigh... searching is redundant, not guaranteed to be sorted the same, not guaranteed to be up-to-date, and updates are not guaranteed to be correct. your notes will last forever, whether or not the software changes under your feet.
I (try to) take notes, and look around once i see a deprecation warning.