I like to steer away from altar calls. In the parable of the sower, the seed that sprouts quickly also dies quickly. While there are those who have passionate, sudden conversions, the overwhelming majority of us have longer, more methodic conversion stories.
It would be great if a pastor could preach a sermon on patience, and everyone leaves more patient, but the word of God grows within us. Altar calls try to push premature sprouting imo. And when the person commits on the spot, then falls back later on, it becomes either a discouragement to them, or you get chronic altar call responders who go up constantly thinking that act will sanctify them.