I have learned so much commonsense during my year in construction school. Here’s a gem I picked up on our class field trip to the Journal of Light Construction’s Remodeling & Deck Show at Music City Center in Nashville.

When it comes to hanging doors, carpenters will often get a call back about eight months after the job, when changes in weather cause wood to shift and doors to sag. Depending on how the door was hung in the first place, the remedy might be really simple. For example, if you used one long screw in the top hinge to go all the way through the jamb and into the framing, then all you have to do is take an impact driver and tweak the screw a turn or two. The door should lift up enough to swing properly again.

But wait! The presenter at the Remodeling & Deck Show advised before making that simple adjustment in front of the homeowner, try this:

Ask the homeowner to get you a glass of water. Or to boil some water. Or whatever. One errand is as good as the next, so long as the homeowner scrams for a minute so you can go about your door-tweaking business unobserved. Because you don’t want anyone to see what you’re going to do.

I was certain the presenter was going to explain the ruse was in order prevent the homeowner from being embarrassed (or irritated) about paying a professional for a simple turn of the screw. But no, there was actually another reason. If the homeowner saw how simple it was to tweak the hinge screw, he or she might be tempted to make the repair next time seasonal changes caused the door to shift, in which case, he or she would likely overdo it with the impact driver, stripping the screw and making the door problem worse.

But that’s just our little secret.