I know this has been asked before, but it seems like every situation is different.
We hired a Rabbi who is not affiliated with a synagogue. He charges an "honorarium" of $600. We met with him initially briefly just to decide if we want to hire him. Then we met with him for maybe 20 minutes when we showed him our ceremony draft. He will be preset at the rehearsal, which we don't expect to take long. And then of course he will perform the ceremony, which we expect to take about 20 minutes. We've decided not to do a Ketubah (FI is not Jewish).
We invited the Rabbi and his wife to the reception but they declined the invitation.
So based on all that, are we expected to tip him like we would tip another vendor? Not to trivialize his importance, but he is the most highly paid vendor (per hour) that we have and 100% of his fee goes to him. I don't want to seem cheap, but I don't know if a tip is really a good idea in this case. Should we get him a box of chocolates or a CD or something, or is his payment and a thank you note sufficient?