Return envelope question

a6a14173

On the return envelope the one with the response cards, I am putting my address in the 'to' spot and a stamp. Should I also include the recipient's return address or is it a thing that they fill in if they feel like it? The envelopes have correct postage and a clear address in my best primary teacher printing

itzMS

FWIW, not one of my RSVPs came back with a return address written in. I've never included mine when sending back RSVPs, either.

a6a14173

Thank you both for your responses.