We had one of these systems in the garage in Essex. "Her" beeper always opened it. Mine never did. Not that it mattered: it was billed as a two car garage in the sales particulars, but in reality that only worked if one of the two cars was a bicycle. Since she was last out and first home, her car went in the garage and mine stayed on the drive.
Eventually her beeper wore out - it was a pretty flimsy thing. I tried to buy a new one.
Ah no, sir, the EU has changed the frequency they work on and we can't sell you a 416 MHz one. You'll have to move to the new 800MHz band. Oh, and that means a new receiver. Oh, and our new model receiver doesn't work with the controller and motor system you have, and the linkage to the door has been upgraded and ...
... so that would be <some silly sum in thousands of pounds> because a little placcy bit in her beeper had broken.
Which is where my non-working but unused beeper came in. I dismantled them both, and made one good (working) one.
It was still working when we sold the house.