part of the furniture
US /pɑːrt əv ðə ˈfɜːrnɪtʃər/
UK /pɑːrt əv ðə ˈfɜːrnɪtʃər/

1.
parte del mobiliario, elemento fijo
a person or thing that has been in a place or situation for so long that they are considered a permanent, unremarkable, or indispensable feature of it
:
•
After working here for twenty years, John has become part of the furniture.
Después de trabajar aquí durante veinte años, John se ha convertido en parte del mobiliario.
•
The old clock in the corner has been there so long it's just part of the furniture.
El viejo reloj en la esquina ha estado allí tanto tiempo que es solo parte del mobiliario.