Depends totally, on the job that you do and the size of the meeting.
For large group presentations (won’t call them meetings), camera off. Detracts from slides and content – same for the speaker to be honest – would rather just see the info on screen, not 20-30 faces.
Would be pretty odd for someone to have a camera off during a 121 though. Ours default to ‘on’ so why would you feel the need to turn it off for a 121 if the other person has theirs on?
For small team meetings / updates, again it’s odd if you have half on and half off.
To be honest, IME, like it or not, there is a trend that those off camera are the ones who, after a long pause, will suddenly answer the question that was posed to them with a ‘Can you say that again?’
That’s just about two years of experience working OOO. Make of it what you will.