I'm not sure where we have all used fast passes, but they were very helpful at WDW, Disneyland Park, SFMM, and Canada's Wonderland. Now that I think about it, Cedar Point, SFGAM, and SFGAV were so busy at the times that I had been there that I should have gotten them. Also Universal and Disney have "single rider lines" on some of their rides that cut the wait to 5 to 10 minutes.