It isn't the %, it's the lifestyle and money left over each month.
I agree with this. If you earn $50000 a month then it would be pretty easy to live on half of it! I prefer to calculate how much we need per month for all the costs BESIDES rent/mortgage then figure out how much we can afford to spend on rent mortgage based on that. If what you need to live on is only 40% of your income then why not spend 60% on rent/mortgage? Whatever you can afford and works for you.