Looking for Wisdom

A man that is an heretick after the first and second admonition reject;

Knowing that he that is such is subverted, and sinneth, being condemned of himself.

Titus 3:10-11

These are my verses for today.  I am struggling with knowing how to apply these in the context of evangelism.  When does a person cross the line from unbelieving/unsaved and in need of the gospel to a heretic who should be rejected after the second admonition?  Can nonbelievers be heretics or is that term reserved for those who claim to be Christians but promote heresies and subvert the gospel?  Lots to meditate on today.