for as long as I can remember
Han estado peleándose desde siempre.
They've been fighting forever.
I've always been a communist.
Sabe coser a máquina y hace su propia ropa desde siempre.
She knows how to sew by machine and has always made her own clothes.
Bueno hay una chica que he querido desde siempre.
Well there's a girl I've always wanted.
Venga, déjate de rollos, nos conocemos desde siempre.
Come on, stop messing around, we've known each other forever.
— El salario del miedo (1953)
Parece que te conozco desde siempre.
It feels like I've known you forever.