Interesting, but I think how much you need is none of their business at the beginning of your relationship. How much you need depends largely on your healthcare needs, child or adult care needs including educational and developmental needs, current level of debt, etc. There's also a lot of subjectivity involved - do you need to travel across the country to visit your parents? Do you need to take a $1000 webinar to refresh/expand your skills? Do you need gigabit connectivity? Do you need a fuel efficient car?

How would he have responded to one of these replies?

"I need x dollars annually. That's also how much I want."

"How much I need is a personal question that I don't feel comfortable answering. How much I want is ..."

Or even,

"How much effort do you want me to put into my work? How much effort do you need me to put into my work?"