I don't comment on her outfit these days. In her old clinic, I would sometimes comment if she wore this white doctor's coat mostly because I've white coat anxiety.

Once or twice (over several years), I've expressing mild concern in the form of our shared culture when she seemed to have lost a bunch of weight to the point of looking unhealthily skinny. And I only did so after clinic staff themselves had made some remarks on her workload and "she's looking so skinny now." in concerned tones.

I myself am often underweight due to some issues - not deliberate restricting - and I do get remarks by clinic staff and medical professionals when it drops past a certain point.

At our current clinic, I've made brief comments about whatever room we happen to be using (if new to me, as there's not always a assigned room per therapist), and if the familiar room has changes in it.