Scripture says that, when Jesus died, he broke the power of sin. Sine does not rule over the Christian any longer.
Except we keep sinning.
There is a reality of what God did on the Cross. And there is a reality of what goes on in our lives.
The penalty for sin was broken in our lives. So, if we have given our allegiance to Jesus, we are assured that we will be with him for eternity.
The power of sin was broken in our lives. Sin does not command us anymore, even if we are not 100% fully free yet. Even if we will never be 100% fully freein this life. But without Jesus breaking the power of sin, here and now, there is no hope of ever overcoming sin in this life.
I, personally, do not think a follower of Christ will ever be sin-free in this lifetime. But I do think there can be substantial growth in this lifetime.
There can be, and there will be, habits and practices that we have, that we know are wrong in God's sight, that will be replaced with God-glorifying habits and practices.