From InDesign CS6 onwards, it is possible to set a text frame to automatically resize based on its content. The direction of this auto-sizing can be specified (e.g. downwards only, both down and to the right, etc.) and minimum sizes set. This functionality ensures that text will never go overset in that frame.

Coupled with anchored objects, this functionality can be a powerful tool for ensuring that the design and layout of your document is maintained throughout the translation process.

NOTE: Because it is not possible to set a maximum frame size, an auto-size frame could grow over other content, or even off the spread. If using this functionality, it is advisable to pseudolocalize the source text to check what might occur during translation.