Mid 50's used to wear thongs, gave up mid 40's.
Like PPs I tend to wear Brazilian briefs often from M&S.
Like another PP I buy 2 x knickers with a matching bra, I like matching underwear even though nobody else sees it! No nude or white, only bright colours to make me smile!
Post mastectomies, I can only wear wireless bras and that makes choice a bit limited although it is getting easier with more choice around.