The Bible teaches that we will not be completely freed from our sin until we are glorified in the New Heavens and the New Earth (see 1 John 1:8, 3:2, Revelation 21-22). Therefore, while still on earth in this age, the Church continually needs sanctification and the mortification of the flesh in believers. One of the main processes of sanctification in the local church is church discipline (see Matthew 18:15-20). Because of this, if a local church does not regularly practice church discipline as laid out by Jesus Christ it is not a sign of health in that church. Rather, the lack of the regular practice of church discipline can only be categorized as unfaithfulness to Jesus Christ and a lack of love for the members of that local church.
I am not suggesting that a local church must regularly practice the third level of discipline that Jesus gives us (bringing an unrepentant sinner before the church and then excommunicating him if he refuses to repent). Certainly if the situation requires this level, it must be practiced. But, the goal is that the first level (privately going to your brother to show him his guilt), or maybe the second level of church discipline (taking two or three witnesses if the first level did not bring repentance) would suffice to bring the sinner in question to repentance.
The upshot is this: our churches must practice church discipline if they are to be healthy churches. And the excuse that there is no reason to practice discipline in one’s particular local church cannot be used. Sin is universally present in all of our lives (and all of our churches); therefore we all need regular church discipline. To fail to regularly practice local church discipline is to be unfaithful to Jesus Christ the King and Bridegroom of the Church.