It depends on the situation.
If I know I’m correct (I’m a subject matter expert in the field I work in), I generally don’t preface my comments.
But in related fields, where my knowledge is less sure, I do.
It can really get difficult, when someone else is talking out their arse, but sounding confident. There are situations where it is unprofessional, to not correct the course of the conversation.
Around 5 hrs to fully metabolise caffeine. Physically you would be fine in a day.
The habit, however would take longer to get over. That depends on your psychology, I know I can’t just replace my morning coffee with tea, because it doesn’t feel right.
I usually have my last coffee at around 2pm, so by the time I get up in the morning, there is no caffeine in my system. The feeling of drinking coffee and tea is different for me, it’s not just about the taste.