Never. We switched over to the One Channel as soon as we got the chance so we could familiarise ourselves with it. We knew how we wanted our branding to go for our small collective, and started with the avatars, then evolved from there. I'm due a banner update as we've got an extra member on the team, but that'll be a subtle redesign as opposed to a complete change.
I'd like to think we got it right first time - speaking as an artist, I don't like lots of change and familiarity breeds a comfort zone that can nurture. It also helps that we use the same artist(me) for all our art needs, reinforcing the idea our small group is united and helps each other quite a bit - what's that? A person commented on a video and they have a similar avatar to the person who owns the vid? Maybe check them out? Cool!
This, more than anything else, means that we've had to get the branding right first time. And to date it's worked well.