This morning, I had a question posed by a former student of mine from quite a few years ago, who is now in law school and a Facebook friend. He wrote:
"Style question for you: if you're wearing a suit with braces, is it necessary (style-wise) to also wear a belt? I would think not (and I often prefer the more classic look of braces) but of course the braces are typically concealed by one's jacket, and so it may appear that one has simply forgotten the belt."
This very question has been addressed often elsewhere in the menswear blogosphere, but here is my take on the matter.
If and when you are wearing braces, as I hope you are with a suit, definitely do not add the belt. It's not necessary and looks silly. You might also consider having a tailor remove the belt loops from said suit and simply wear braces when the suit is necessary. Or you just feel like wearing it.
Removing the belt loops makes for a smoother, more finished look in the case of a suit, which is desirable. That is something I ought to do myself, since I have several pairs of dress pants plus a few suits with brace buttons on the inside of the waistbands, and I categorically never wear a belt with these items.