This Hadith will answer your question..

Narrated Abu Huraira: I heard the Prophet saying, “If somebody commits a sin and then says, ‘O my Lord! I have sinned, please forgive me!’ and his Lord says, ‘My slave has known that he has a Lord who forgives sins and punishes for it, I therefore have forgiven my slave (his sins).’ Then he remains without committing any sin for a while and then again commits another sin and says, ‘O my Lord, I have committed another sin, please forgive me,’ and Allah says, ‘My slave has known that he has a Lord who forgives sins and punishes for it, I therefore have forgiven my slave (his sin). Then he remains without committing any other sin for a while and then commits another sin (for the third time) and says, ‘O my Lord, I have committed another sin, please forgive me,’ and Allah says, ‘My slave has known that he has a Lord Who forgives sins and punishes for it I therefore have forgiven My slave (his sin), he can do whatever he likes.” (Al-Bukhari, Book 93, Hadith 598)