A current thread reminded me to ask this question.
My young sons and I have a little ritual as I kiss each of them goodnight and tuck them into bed, as follows.
I say: ¿Quién te quiere?
He says: Papi
I say: ¿Cuánto?
He says: Mucho
I say: '
He says: Para siempre
The ' would be "For how long'" in English. I'm not sure whether this should be ¿Para cuándo', ¿Hasta cuándo', ¿Por cuánto tiempo', or something else. Up to now I have been saying ¿Por cuánto tiempo', but I wasn't sure if por and para could be used with each other in this way.
What would be most natural in this sequence? I don't want to be teaching my boys bad Spanish (any more than I already am!).