I take the opposite approach:

As a highly experienced researcher, I have lengthy discussions with users when I'm in that needfinding stage. I ask questions from different angles to really dig deep into their needs, behaviours and attitudes. I only need a way to contact the person and a tape recorder, but I've had years of intensive training and mentoring from best-in-class researchers on how to ask the right kinds of questions.

Once I have a very firm handle on user needs for a particular persona, I don't need to do it again for the same user. A team I was working in once tested six prototypes for totally different products based off the same initial research - the person was the same, but this was just approaching those established needs from different angles.

As a consumer, I'd never respond to an invitation like that. We compensate fairly for research (about $100 per hour).

Once you've completed the generative research, you can focus on the evaluative (usability etc.) side - and it looks a little from your summary like you're conflating the two.