As discussed elsethread, asking how you sound as you switch between headphones and speakers doesn't tell you anything. People who don't wear headphones make others sound bad (when the echo cancellation software fails).

I experience this problem all the time: Zoom, Whereby, Google Meet, Slack etc. If people are disciplined about muting their mic when they aren't speaking, that helps. But as soon as you have one participant listening in without headphones and an unmuted mic, if the echo cancellation doesn't work then whoever else is speaking will sound bad.

I’m just saying that I’m in meetings probably 4-5 hours a day with usually between 3 and 15 people and the proportion of people wearing headphones is probably 20%. We don’t seem to have echo issues, though with previous conferencing software this was sometimes an issue. I used to use headphones but they don’t seem necessary any more. Maybe Teams is just good at this?

Things have almost certainly improved at least on some platforms. I do wear wireless headphones (but use a wired mic) for critical recording situations. But, yeah, tons of the people I have on my often hours of calls a day are not wearing headphones/earbuds and I just don't hear the problems that the "never use speakers" folks raise.

And I've never used Teams. Combination of Bluejeans, Google Meet, and Zoom mostly.

If I were this rogue speaker person ruining things for everyone else wearing headsets, I'd maybe accept that I was a general problem. But that's just not what I see.

(As I noted in another comment, it's also true that if we talk over each other, it's mostly accidental.)