Does the best man usually give his speech at the reception after the wedding or at the wedding rehearsal the night before? I am the best man and I have never had to do this before. I tried googling it but it says it both ways.
I always remember it at the reception after the wedding.
However, I believe the correct response to your question is: whenever the bride and groom want it to happen. After all, it's their wedding. Just ask the groom which setting he'd prefer.