Station 01 / 05
The product you're building — how urgent is the problem it solves for users?
Station 02 / 05
Not how often they could use it. How often the problem actually occurs in their life.
Station 03 / 05
More alternatives means more evidence the problem is real — but also more to beat. The sweet spot is "obvious problem, weak existing solutions."
Station 04 / 05
Not "do people use it" — that can be habit, politeness, or sunk cost. Do any users, unprompted, tell someone else about it?
Station 05 / 05
Not motivation — that fluctuates. Conviction: when things go wrong, do you still believe in the problem? Or are you working on it out of momentum?