Yeah, I google, tealdear, "--help", and manpage anything I don't use at least once a week, every time. Usually I don't remember them otherwise, and if I think I do, I don't trust my memory that well. Only exception is if I remember enough to be able to ctrl+r them out of shell history faster than I can do those things—and actually, for some of those, I
do use them often, but couldn't possibly tell you how because I only run a couple commands 99% of the time and always pull them out of history unless it's one of the rare exceptional cases—I couldn't rsync for a particular outcome without consulting a reference, to save my life, even though I use it often.
And usually you only use a fairly small set of tools that often, in any job, and which set will depend on the employer, how things are set up, and what exactly you're doing.
Oh and somehow I get "-r" versus "-R" for "recursive" wrong almost every time, even for commands I type almost daily, unless I check first. It's weird. If tools could get on the same damn page about which means "recursive", that'd be great.
TL;DR I do have a pretty good idea what I'm doing, but look like an absolute idiot if anyone watches me do it. Much worse, even, if I know they're watching and we're not in some kind of relatively high-trust relationship (so, definitely not in an interview setting).
