I took a bit of a break from black - tried to incorporate more navy and also blue (as in denim). As for navy, I did not have much luck because of petite reality (core items are offered most reliably in black, not navy). I had much better luck with denim blue (one positive of my weight gain this past year is that I find it easier to find jeans). But you know what? I'm already bored of navy & denim!! I found myself missing black... around the middle of the summer...
I have no idea if it favors me but dang it is practical for packing and frequent business trips/travel.
As for aging + black, I could be wrong but I think it was my hair color that was more aging than the black clothing. For years I've been able to pull off very light blonde.... but more and more this year, I felt like the same usual highlights were washing me out and looked aging. So I have recently chosen to add in deeper lowlights - caramel, red, gold. Those never looked quite "right" next to my skin in the past... but now they do.
The only problem is that they seem to lighten right back up again in no time at all ... though I still am only maybe 20% gray(white), something has happened to my hair in recent years, as it's naturally more light blonde than ever... according to my stylist.
I don't know if this applies to you, Una. For me, the difference is very subtle -- but with lowlights rather than highlights I'm finding black works again.