<prompt> Human: I always hear personal finance advisers saying that individuals should never be spending more than 33 of their income on housing rent or mortgage. This might be a stupid question, but why? Why shouldnt we aim for 20 or allow us to spend 40 on rent? Why dont we just try to pay as little as possible? Is there a reason for the one third rule?  <response>: This percentage depends on a lot of factors.For example, if you live in New York City you may need to spend more and that might make sense. If you have no cars or other commuting expenses, that frees up money for housing. 