So, I hear that touted as "conventional wisdom", but it's not particularly clear why. As long as you aren't spending beyond your means, what's wrong with allocating more money to housing? Say I want a bigger apartment, and I'm willing to drastically cut back on restaurant outings to make up the difference. How is allocating 50% to housing and 25% to food (assuming that 25% buys you healthy meals all year) less sustainable than allocating 25% to housing and 50% to food (talkin' 'bout some pretty nice food here)?