Can attest to screw connections working loose over time. I recently posted about a junction box I had installed on a floor joist about 5years ago only to find when I added a spur to it I found the screws gripping OK but definitely not tightened to my usual torque of one grunt + 1. At the moment it is easily accessible as the floor is carpeted but SWAMBO is talking about replacing the covering with Amtico or Karndean so will probably replace it with a Wago box before that.

Richard