It varies greatly. Most of the time you just walk right on or wait just a minute or two, other times, you can wait 15 minutes or even a little longer. I think the longest we had to wait for a FastPass return was for Voyage to the Little Mermaid. We got there right when the return time was and we waited for what seemed like an eternity in this little, hot room that had no entertainment while we waited. It was probably only 15 minutes, but it seemed like forever.