As I fly out of ZRH, which is usually ridiculously expensive for J or F on longhaul, I pretty much always am on separate tickets. I usually try to spend a full day wherever I'm connecting. I figure enjoying a day in the connecting city each way is all part of the fun. TBH, I would have spent a couple of days in DUB the last time, but it was difficult to find a flight and hotel room for DUB.

Last year, it looked like I might get cancelled on my ZRH-LHR, so I booked a Y ticket using Avios on the first flight of the next day, when my longhaul was leaving. My flight the day before went out with minimal problems, so I ended up burning the Avios and the RFS cash for that Y ticket. But it was worth it, for the peace of mind. Not to mention the couple of thousand franks I saved on the trip.