Every detail "costs" some render time. It'a matter of deciding wht you don't need.
ray traced shadows and reflections, numerous ray traced lights, complex combiner materials, "roughness" on a surface... those are things that increase render time.
Mapped shadows, simple lights, simple materials, smooth surfaces... they are quicker.
If you just want to check the motion of an animation, test render it in shaded mode. That is very quick.