How can a pastor know when his congregation is ready to practice church discipline?

You know your congregation is ready to practice church discipline when:

Your leaders understand it, agree with it, and perceive its importance. (This points to one more reason to have a plurality of elders: in addition to being scriptural, a plurality of elders helps the lead pastor shoulder the burden of leading a congregation through the difficult task of discipline.)
Your congregation is united in understanding that such discipline is biblical.
Your membership consists largely of people who regularly hear your sermons.
A particularly clear case comes along in which your members would, more than likely, all perceive that excommunication is the correct action (for example, excommunication for adultery is more likely to yield agreement among members than excommunication for non-attendance).

(This material has been adapted from Mark Dever’s article, “Don’t Do It!! Why You Shouldn’t Practice Church Discipline”)