If I may reply: We are not sinners saved by grace, we WERE sinners saved by grace. Now saying that, I am not implying sinless perfection. At salvation we are created "new creatures", which implies the old man (and his ways) are gone. Now Christ/ the Holy Spirit abide with us. Christ also being our Great High Priest making intercession. That isn't to say that we aren't tempted and sometimes yield, that isn't to say that the sanctification is complete. It is saying that we are sinless immediately after conversion, yet we still reside in this world and are still free moral agents, needing to be continuoslly cleaned when fighting against the flesh. Warring in the flesh (Rom 6). So to answer your question: No, I don't believe sin in a christians life is normal, (if we are talking about knowingly/habitually committing of sin). Now sins of ignorance and possibly a sin that the christian is warring with (has not received victory over yet, (and knows it to be wrong...seeking forgiveness at each offense), I would not call it NORMAL. As long as we are genuinelly serving Christ we will constantly be at war with the sin nature, but glory be to God and the Lamb of God (our Saviour and High Priest), it doesn't have to reign (have dominion) in us.