1-2 months of work building the prototypes or 1-2 months of work building, iterating and getting commitments, or 1-2 months of work building a launchable produc

1-2 months of work building the prototypes or 1-2 months of work building, iterating and getting commitments, or 1-2 months of work building a launchable product based on them? Paper prototyping is HUGE. I don't get why more folks won't or can't embrace it. Not only can you do the testing that you have suggested but your engineers and designers will THANK you. There is a huge upside to paper, UI issues can be spotted early and cheaply.