Millington's housing stock centers on 1972, which puts it at the early edge of the 1972-2005 range for the areas we cover out of Bartlett - meaning the hardware here has had more years to wear than in the newer pockets closer to Germantown or Wolfchase. A torsion spring is rated for a cycle count, not a calendar date, and a door that's opened twice a day for fifty-plus years has burned through that count a long time ago, whether anyone noticed or not.
The region sits in a cold-moderate climate band, which isn't brutal but isn't nothing either - temperature swings through the year work on steel the same way they work on anything else, stiffening lubricant, tightening tolerances on cold mornings, and that's usually when an old spring finally lets go. It's not a coincidence that a lot of these calls land on the first genuinely cold morning of the season.
With roughly 4,469 households in Millington, a good share of them are sitting on hardware that's never been inspected, let alone replaced, since the house was built.