Checking It Yourself
Look at the two small boxes low on either side of the track, a few inches off the floor. Each has an LED. On a working pair, both lights are steady - one usually green or solid, the other sometimes blinking to show it's receiving a beam. If one light is out, or flickering when you nudge the bracket, the eyes aren't lined up anymore.
Run a broom handle through the beam path while the door is closing. It should reverse immediately. If it doesn't, stop using the opener until you fix it - a sensor that fails to trip is a door that can close on a car bumper, a pet, or a kid, and that's not a repair to put off.
Most of the drift you'll find isn't the sensor itself failing. It's the bracket. In a lot of Rochester Hills garages, that bracket is original hardware, screwed into wood framing or a masonry anchor that's had decades to move. Wipe the lenses first - dust and cobwebs cause more false alarms than actual misalignment - then check whether the bracket itself has any play in it. If it wiggles, that's your answer.
What You Pay
We don't have a set number to give you here, and we'd rather say that than make one up. A sensor job runs from a five-minute realignment to a bracket replacement to, occasionally, a wiring problem that takes longer to trace - and the honest price depends on which of those you actually have once we're standing in front of it.
What we can tell you: if a technician quotes you a full opener replacement for what turns out to be a bent bracket, get a second opinion. The sensors are one of the cheaper parts on the whole door, and in most cases the fix is realignment or a new bracket, not a new system. If your opener is old enough that parts are hard to source, that's a different conversation - but that's a decision to make with actual eyes on the unit, not over the phone.
What Local Conditions Do
Rochester Hills sits in a cold, severe climate band, and that matters more for sensors than most people expect. Concrete slabs heave a little every winter as the ground beneath them freezes and thaws, and a garage slab is no exception. That movement is small - fractions of an inch - but a sensor beam only needs a fraction of an inch of vertical shift to miss its target entirely.
With 122,221 owner-occupied houses across the service area, most sitting on slabs poured in that same mid-century stretch, we see this pattern every year: sensors that worked fine in October start acting up in January, then seem to fix themselves by May. That's not a coincidence and it's not the sensor failing - it's the slab moving with the frost line and moving back. If your bracket is mounted straight to the slab or a masonry pier rather than to the wood jamb, you'll feel this more, not less.
