Hakim al-Umma Mawlana Ashraf Ali Thanawi (Allah have mercy on him) said  something smilar to the following in one of his discourses,

The minimum  benefits of maintaining regular correspondence with  a Shaykh ( in form of islahi-ta’luq) is that it makes an individual a cognizant sinner (baydar gunahgar).

That is, if God-forbid he commits a sin he will be aware of this mistake. He will have remorse. This will evetually lead him to turn to Allah in form of repentance and supplication for forgiveness, protection and improvement.