There could be different levels of model prototyping as well just like drawing; quick 1 minute sketch to hour+ hand rendering in full color. If time/budget allows, I could go through 6+ models in various scale and materials before making the 1st full scale prototype for a chair. From 1/8 scale foam core, to full scale cardboard, to full scale wood mockups. Once I get the proportions figured out then I make the 1st trial in wood with proper joints, etc. For packaging I’d make (depending on the size) various 1/2 scale paper models, then 1/2 cardboard, then once satisfied with the design make full scale cardboard before sending the files to the factory for factory-finished prototypes.
The 1st model should be quick, fast, and inexpensive; don’t spend too much time as you will find refinements needed. Once you feel comfortable enough on your design then make the next models with more effort and better materials. I always use 3d CAD to help with all stages of the process as well; though personal preferences will change for everyone on their workflow.