Depends on the shape of the trousers, what shoes you're wearing, what your preference is and what's fashionable at the time. Personally I like a slight break in the crease at the front of the shoe and a taper down at the back so the back crease almost touches the top of the heel of my shoe. Then take a walk about and check they don't swing about and adjust if needed. That's a good timeless rule to stick to and since suits last quite a long time will guarantee what you get done won't make you look silly when you turn up at a funeral/wedding in a few years time.anyone got an pics as a guide to where they should finish?
The bottom of the trouser should be at the start of your heel. Not the back of the shoe but the start of the heel.