The main reason why a survey can take much longer than expected is that you are being rerouted from the original survey to another. You'll notice this if you have to answer the standard qualification questions about your living and job situation, say, 4-5 times at the start of "one survey." This will only happen with a few survey partners (again, not from CPX, InBrain, TapResearch, or BitLabs), and it's because some of them will redirect you to another survey if they notice you didn't qualify for the first one you wanted to do. So they reroute you to another one that may or may not match - and if that doesn't work, they reroute you to another.
