I do use that keyframing method as a rule, but I often find that even 4 frames without a keyframe is enough to break the tracking. Also, this shot had a bit of camera bounce at times, which required such attention.

I was having a lot of jittery tracking on the X-wing approach to the Starkiller, and after investigation I realized that it was due to not knowing exactly where the replacement matte should be. This can be mitigated by tracking using an unaltered still (the piece that you want to replace) allowing for precise matching of its location through the shot. After getting an exact lock you can alter the still and it will retain the movement.