AZ, I have been involved in shidduchim that went 3 or 4 dates and then fizzled out. And I have known couples who canceled 3 weeks before the wedding. As the shadchan involved I wouldn’t want to get compensation if it didn’t go through. I have set up many, many couples who have told me I am on the right track and I have “listened and understood” them, but it didn’t click with that particular person. Unfortunately or fortunately I was only lucky enough to make one shidduch for my own niece, but I was always successful in getting it right. On the other hand, I have coached many young people through the shidduch process and that could mean 1 date, 3 or 4 dates or all the way through to the wedding and beyond.
I don’t believe a shadchan should get paid until they go to the chupah. It is not a done deal unless their is a marriage no matter how hard a shadchan works. A salesman that pitches a sale for 5 weeks does not get paid until the merchandise is paid for even if the sale goes through. That is the nature of the business. There is a double edge where Shadchanim are involved it is not only a business it is also a mitzvah and therefore it has to follow Torah guidelines and not new convention.