I had a bra fit in Poland last year after reading a NYTimes story about their bras and fit techniques. It was quite worthwhile and I learned a lot about where the support actually comes from (the band so it must be tight).
i travel with one of the two I bought, but the strapless one is padded and well formed so I haven’t ever packed it because it takes too much room and I don’t want to crush it. If I was doing that over, I would have not gotten the same type. Most of my cups are thin and crushable.