Anyone who’s seen a user trying to get to grips with their application knows what a humbling experience it can be. No matter your design experience there’s no substitute for testing with actual users. But the whole user testing process can seem daunting & costly in terms of time, effort & materials. Seeing this Jakob Nielsen proposed a lightweight approach, ‘Guerilla User Testing’, in the mid-nineties. It emphasized what could be done on limited resources by a team committed to providing a decent user experience. Marc & Luke share over 20 years of experience applying this type of technique.