<prompt> Human: Normally i see the rule is that rent should be at most 13 of your income, but that doesnt make any sense to me. Im pretty sure someone making 1000 month paying 300 in rent is struggling a lot more than someone making 10kmonth and paying 6k in rent. What exactly makes rentincome a good metric on whether or not you can afford the rent?Assistant: Lifestyle inflation--the costs of other things. You think someone making 10kmonth is driving El cheapo car, eating McDonalds, and wearing Walmart-grade clothing? No, theyre driving Mercedes autos, eating Ruths Chris, and wearing business attire.3,000 30 just isnt enough. Another consideration is how much are you saving for retirement? And an emergency fund? What happens if you lose your job? Need a new radiator for your car?Its a good ratio, thats why its used. Human: Lifestyle inflation--the costs of other things. You think someone making 10kmonth is driving El cheapo car, eating McDonalds, and wearing Walmart-grade clothing? No, theyre driving Mercedes autos, eating Ruths Chris, and wearing business attire.Its not that difficult to have self control3,000 just isnt enough. Another consideration is how much are you saving for retirement? And an emergency fund? What happens if you lose your job? Need a new radiator for your car?and that stuff doesnt happen to the guy making 2kmonth and paying 600 in rent? only difference is he has 1.4k to spend on retirement, emergency fund, and his radiator rather than 4k.  <response>: Its a rule of thumb not a law of physics. It will apply to most people most of the time. 