I attend a number of black tie events, mostly dances or benefits. In fact, since I retired last year, I've worn my tuxedos much more frequently than my closet full of suites. I think some of the suites are going to charity, and a sport coat or two might be cut down to wear with a kilt (which I hope to order next week). I'm not sure I will bother buying a formal jacket to wear with my kilt, but if I had one I would keep it. For me, once a year is enough reason to keep a piece of clothing IF I LIKE IT. However, this advice id from a man who still has almost 200 neckties that are collecting dust.