How Local Conditions Play In
We're in a mild temperate band here, not the wide freeze-thaw swings that crack concrete slabs up north. That actually works in your favor on some fronts - you won't see the frost heave that racks a track out of square. But mild and stable still means the garage floor slab and the track mounting posts expand and contract daily with sun exposure on the door itself, especially on west- and south-facing bays that catch afternoon sun most of the year.
That daily cycle is small, a fraction of a degree at a time, but it's constant, and constant beats occasional. Over years, the bracket screws work themselves a hair looser, the bracket rotates, and the beam that used to line up dead-on now clips the edge of the receiving eye. You'll notice it first on the door that gets the most sun, not the one in the shaded side of the garage.
Humidity plays a secondary role - condensation on the sensor lens itself can mimic a misalignment symptom, showing an intermittent fault that clears up once the lens dries. If your door only misbehaves in the early morning, check the lens for moisture before you touch the bracket at all.
What to Look At First
Before you call anyone, look at the two sensor eyes yourself. They should be pointed straight at each other, roughly six inches off the garage floor. A small LED on each unit tells you the story: solid means it's receiving a clean beam, and most units flicker or go dark when misaligned.
Check the bracket itself for play - grab it and see if it wiggles. On a lot of the older openers common in homes from the 1960s and 70s stock in this area, the bracket is held by a single sheet-metal screw into a wood jamb that's had sixty-plus years to shrink and loosen its grip on any fastener. If the bracket rocks in your hand, that's your answer, and it's a fastener problem before it's an electronics problem.
Next, wipe both lenses with a dry cloth. Spiderwebs and dust film cut the beam strength enough to cause intermittent faults that look identical to misalignment. Only after you've ruled out a loose bracket and a dirty lens does it make sense to check the wiring at the sensor base for a corroded or pinched connection.
One honest limitation: if the bracket mount itself has rotted or split, tightening the screw won't hold - that's a bracket replacement, not an adjustment, and it's worth saying so before you spend an hour chasing an alignment that won't stay put.
