I would only use an exotic or black Birkin 25 or Kelly 25 or 28 cm (for me, sellier black box) for evening. Otherwise, they are day bags, IMO.
You can get away with a Kelly 32 at a dinner party. An evening gown requires a mini Kelly or clutch, IMO.
OK - I get the picture now. This is really what I needed to know. I think I was only equating night with gowns, being so simplistic in my assumption, hence my own confusion.
It sounds like you really don't want or need another Birkin. I wouldn't buy one just because it was offered to you, although it's always tempting! Vache Liagee is EXPENSIVE! get only the Hermes bags you can't live without.
My husband would say he is the only one I can't live without! LOL and that I most certainly can carry on living without more orange boxes!