How often they do this depends on their goals and their personalities and varies from sign to sign.
Aries
Aries people always tell the truth, you can be sure of that. They say whatever comes into their minds and expect others to behave the same way. They don't care if they hurt someone's feelings by telling what they think.
Taurus
Those born under the sign of Taurus avoid lying because they don't want to get into troubles that can cause additional problems in their lives. However, it happens from time to time that they tell little white lies when they have to.
Gemini
Gemini tries to adjust to everybody and to meet everybody's needs that cause them to lie very often. The lies they tell vary from minor to very serious ones. It happens because they can't distinguish a little lie from a big one.
Cancer
Cancer people lie only when they don't want to hurt one's feelings. They will always tell the truth if they're sure it won't offend anyone. If a Cancer considers that someone might be hurt, he/she will tell a lie since he/she thinks that is the best thing to do at that moment.
Leo
Leos will never lie to you, even if that were his last words spoken to you. They will always tell the truth, no matter how painful it might be, they think that's the right choice. Leos don't want to hurt one's feelings; they just consider that it is the best to tell the truth regardless of the consequences.
Virgo
When they think they're endangered, Virgos will tell lies. If they need to defend their arguments or themselves, lying is inevitable. But if they suspect that others could see through their lies, they'll soften the truth and won't tell the complete lie.
Libra
Libras lie, but not very often and not too much. They will tell a lie only when they find it necessary. They try to be in good relations with everybody, so lies are used only to keep the balance.
Scorpio
When it comes to lying, Scorpio is the number one. They can get entangled in the web of lies so much that they almost become someone else, even their friends and family hardly recognize them. They do this to be the center of attention, and lies are the easiest way to achieve their goals.
Sagittarius
This is the most sincere of all Zodiac signs. Sometimes they tend to exaggerate a story from their life, but that doesn't mean they're lying. They just want to amuse others. The lies they tell are never those that hurt one's feelings.
Capricorn
People born under the sign of Capricorn always have to reach their goals, no matter how. So it is possible that they sometimes hide the truth to realize their ambitions. Their friends and families don't have to worry; Capricorns are completely honest with them.
Aquarius
Aquarians lie only when they think that a lie will improve their relations with others. So don't be offended if they tell a lie to keep the peace and harmony between you.
Pisces
This sign of the Zodiac tends to embellish the truth and sometimes exaggerates to get the sympathy of certain people. They often lie about the past, present, and future situations. There's one thing you can be sure of- Pisces never lie with the intention to hurt somebody.