I like trying different carriers, so that's a bit of a factor, but if the airport is 3 hours away I won't wanna use it. I'd much rather pay a bit more for the fare. 50% more? So dependent on where, time of day, cost to get there, etc etc.
In the end for me there's a threshold on the dollars that will sway me. It's never the same and sometimes it's arbitrary. If the low cost carrier YVR-KIX (AC Rouge) is $899 and UA YVR-SFO-KIX is $1010, I just won't go. If I HAVE to go (which would likely be for work) then I'd go UA. It's only about $120 difference, but if it's my leisure dollars, jumping past $1000 is a major hurdle for me, it's there at $500 as well.
Went SEA-IAH-EWR-SJU and return, it was like $350. I hadn't planned on going but it was cheap. Making less connections and flying from YVR was like $550, which I wouldn't have done.