Yep, it really depends on the airplane. If it is something like a sport plane, warbird, etc. I generally start with no expo on low rates and minimal or none on high rates. I only add expo if I think it will help after flying the airplane. Sometimes on those kinds of planes, just taking out some throw will eliminate the need for expo too.

If the plane is a fun fly or 3D type with monster control surfaces and extreme throws though, I try to start out with around 30% on low rate and as much as 50% on high rate. It can always be changed from there.