Very often when we are trying to discern someone's spiritual state, we look at just one factor: Church attendance.
This isn't necessarily bad. It's just intriguing that after knowing if someone regularly goes to a church building or not, we think we've got their spiritual life pegged. It seems to be the only marker we have for someone's Christian faithfulness.
If someone goes to a church service weekly we think they are a pretty faithful follower of Jesus.
If they are involved in those church services weekly we think even more highly of them.
If they don't (or rarely) go to a church service we discern they are not following Jesus.
Don't get me wrong, being with the church is a good thing, a great thing. And it does say something about your spiritual life. But it doesn't say everything. The problem comes when church service attendance is our only marker for someone's spiritual life. Anyone can show up at a building and sit through a service regardless of where there heart is at.
I guess I'm saying: Don't stop at church attendance. Build deepening relationships so you can accurately know others and challenge them to grow spiritually.