How Do You Know When Your Sermon Has Really Hit the Mark?

Relevant preaching is, well, relative, right? For pew-sitters, a 'really good sermon' can mean a dozen things to a dozen different people.

Calvin has a word in his Institutes about the process of sermon-making and sermon-delivering:

"It now remains to pour into the heart itself what the mind has received.  For the Word of God is not received in faith if it flits about at the top of the brain, but when it takes root in the depth of the heart that it might be an invincible defense to withstand and drive off all the stratagems of temptation..."

-  Institutes III.ii.36

Came across this quote in Coffee With Calvin: Daily Devotions, by Donald McKim.

As you preach, is that notion utmost in your mind? Do you equip your parishioners with the necessary spiritual tools to combat those "stratagems of temptation"?