Although lies may benefit in the short-terms, doing bad so good will come isn't right.
We should always tell the truth because one lie can lead to another and another, and then everything falls apart. Even though we should always tell the truth we don't because we're very selfish. For example, if someone asks you if you dropped 20$ you'd say yes yes I did.
I wouldn't say 'always', but play it safe.
if you don't tell the truth than you will get in a lot of trouble
Lying is sometimes necessary to ensure the survival of another human being (e.g. if a proven serial killer asks a dangerous question one should obviously lie since giving him the full truth could possibly lead to the loss of innocent lives)
Normally I believe telling the truth is the better way out, but you do have to lie about somethings, like many Jews in Germany lied about being Jewish, or how some black men may have lied about being slaves in the U.S.
For the most awesome reason to lie, I refer you to the end of the Dark Knight, and its results seen in the Dark Knight Rises.
there is such thing called a white lie which overall saves doing damage to a person than telling the truth which may end up really badly
white lies, lies to protect others, lies to protect yourself, etc
Lying to your parents you done your homework obviously!