As a researcher/strategist with a design background, I think it's reasonable to expect to check in with users 2-3 times before a design is finalized - and hopefully you started from a relatively deep knowledge of the current experience & opportunity before you ever started the project! The key is to know what you are trying to learn from each research cycle. Do you want to know if the idea seems reasonable? Sketch level ideas & storyboard scenarios are the best stimulus. If you want to understand UI flow, you should expect to have at least 70% of all potential outcomes wireframed, but they can look like crap. If you want to understand which of several design directions to take aesthetically, you need more slick-looking screens, but only 1 or 2 navigation paths for each (since the goal is gauging aesthetics rather than functionality). If you want to know if you are ready to launch, you should have the whole thing as finished as possible. And in general, more cycles with fewer people (think 5 core users, 5 extreme users & 5 potential future users) beats fewer cycles with lots of participants.
As a researcher/strategist with a design background, I think it's reasonable to expect to check in with users 2-3 times before a design is finalized - and hopefully you started from a relatively deep knowledge of the current experience & opportunity before you ever started the project! The key is to know what you are trying to learn from each research cycle. Do you want to know if the idea seems reasonable? Sketch level ideas & storyboard scenarios are the best stimulus. If you want to understand UI flow, you should expect to have at least 70% of all potential outcomes wireframed, but they can look like crap. If you want to understand which of several design directions to take aesthetically, you need more slick-looking screens, but only 1 or 2 navigation paths for each (since the goal is gauging aesthetics rather than functionality). If you want to know if you are ready to launch, you should have the whole thing as finished as possible. And in general, more cycles with fewer people (think 5 core users, 5 extreme users & 5 potential future users) beats fewer cycles with lots of participants.