Trousers break

It is nice to have a break because it creates a clean line at the back of the trouser, adding to the lengthening silhouette that is the suit’s main aesthetic advantage. Because when a man is walking it looks more elegant if his suit trousers flap less and expose less of his ankle. 

If the trouser were longer, it would create a puddle of folds that could ruin the silhouette of a suit, dragging the eye down and making a man look shorter. If the trouser were shorter, it would flap around the ankle and remove any elegance – probably reminding the viewer of a schoolboy in short pants.

Men on the European continent tend to wear their trousers shorter than is recommended there. They do that because they wish to expose their footwear, and perhaps their socks, to more inspection. Both are more a part of their outfit than for a English or American man. To quote one famous Italian “I don’t necessarily want people to see my socks, but I want to make sure they can see my shoes.”

Traditionally trousers were always worn to just reach the shoe without breaking. Trouser legs were often quite wide, so flapping could probably not be avoided (maybe by using thicker fabrics)

The traditional length in the 20s/30s Was cut to the shoe level, or even a bit shorter. The flapping aspect was helped a lot by the fact that they wore much thicker materials, largely flannel and tweeds, which do not have the potential airy problems of worsted.