The semi-colon is like a heavy comma. You don’t use it as parenthesis like a comma, but it breaks a sentence in two when both parts are separate but still one sentence; when they could have been complete sentences but happen to be a single statement.
When you have a list which includes commas at certain items in the list, you’ll use a semi-colon to delimit the list. This is how dictionaries use it. In general though, if you find yourself using it too much you are probably misusing it.
I must ask, when and how do you use a pipe, other than in logic?