Originally Posted by Gent
One interesting thing, really, is how a tree-piece suit really limits one's choices of lining. I am of the impression (do correct me if I'm wrong) that the back of the waistcoat tends to be in the same material as the lining of the suit. This would make flashy colours one might otherwise consider, such as red, for example, utterly ridiculous, if one ever wishes to take the jacket off.
Thoughts on this?
I have several 3 piece suits where the vest back color approximates the suit color while the lining, including the vest lining, is brighter.
As to the OP's question, I think you can wear a 3 piece suit in any business situation if, in doing so, you don't look like you're wearing costume. This is a function of both the suit itself and the person wearing it. If you are young and self-concious about the vest, better to leave it off. Also, vests look like crap if the suit has belted trousers.