I still fail the pencil test, but I need a bra.
I started wearing a plain sports bra while still in male mode, about a month after I started HRT, to protect my growing boobies from chafing against my shirt when I exercised. As they started to become visible through a shirt, I started wearing it all the time for concealment, as I was still in male mode.
When I went full-time, I switched to a padded sports bra, for visual enhancement. I stuck with the sports style because that was the only thing that would fit small enough. I have since moved up to a "real" 38A bra.
While I like seeing my boobs through a T-shirt, it is not an image I want to impose on the general public. That's not how a 63 year old lady would look. When it comes to dress and deportment, I seem to channel my mother.

So I always wear one in public.
I wear one around the house and yard when I am working on something. That's for protection: it is just too easy to bonk the girls on something. And I discovered that they need support if I trot down stairs. I always used to trot down stairs, but I have had to learn to glide down stairs when I am not wearing a bra. Even my little A's let me know if they jiggle too much!