A general rule of logos is that they should work well at all sizes. It's worth pointing out, though, that you are allowed to manually tweak them if needed to make them work in certain situations. Craig Hockenberry discusses what he did to make his company's icon work at very small sizes.
The animation to the left shows the progression of changes Anthony made to align the roof and windows of our factory on a 256×256 grid. While we ended up with a shape that’s different than our official logo, it renders a lot more clearly in the space provided.