What should you keep in mind when configuring Compatible Renderings?

They should be set on both components so you can exchange them. Both need to be in the Allowed Controls for any placeholders they will appear in. They may need to share data source and parameters.

They should not be set on both components so you can exchange them. Both need not to be in the Allowed Controls for any placeholders they will appear in. They may not need to share data source and parameters.