<prompt> Human: I was looking at how much do I need to save for retirement. In almost all calculators, although in some I can change some numbers, they assume I will still be paying about the same for mortgagerent. If I buy house now and pay it in 30 yrs by time of retirement, isnt that free housing now, saving near 1500-2000 each month?  <response>: Most retirement calculators allow you to adjust your spending levels for retirement, and most assume something like 80-70 pre-retirement spending. 