I've had a lot more issues re-threading cables through housing than I've had with cable splitters. With the splitters, I've only ever had one problem and that was when I lost 1 screw when changing a cable, so I tried to hold it with just the 1 remaining screw, but that only lasted about 200 km before it let go. I'd been smart enough to put that splitter on the FD cable, so it wasn't a huge hassle to manually move the FD using the limit screws a few times to allow us to complete the ride. As well as spare cables, a spare splitter is now also part of my tool kit for extended trips.