When a believer continues walls in sin and know they are sinning, their effectiveness for the Lord is seriously hindered, and risk losing any rewards that the Lord has for them.
However as previoused stated there are situations in our lives where we battle with drinking, or whatever addiction that takes time to move forward from.
Each one of us have issues that we are personally dealing with, and the only way we overcome those issues is with the love and patiences of the Lord. No one's journey as a Christian is the same, and at times we fall more than we stand, but yet in and through it all, God's grace abounds. He remembers that we are dust, and have feet of clay.