How Much Rent Should You Make?

The typical recommendation is to make 40 times rent. If we go back to the traditional budget, right, which is that you don't want to spend more than 30 to 40%, I'm talking New York City here because New York City is just so expensive. So if we were to use this 40x equation that many landlords will want to see on your application, that essentially comes down to 30% of your gross income,. That's what the finance books recommend. What do you think about that?