<prompt> Human: Dear smart folks at PersonalFinance,I would like an answer to a real estate question so that I can share with family. I personally cant share the answer right now because I myself dont know why it wouldnt work even though i have a hunch that it isnt possible. Background story is that we are interested in moving to a bigger home, and an idea is that we should always own and never rent. Ive shared a rent vs own analysis of NYC to show that this is not a necessarily correct financial analysis, however there is a component of renting out that I dont know the answer to. The basic financial planning idea goes as following:1. Take out mortgage2. Buy a new real estate property, be it a house or a condo3. Rent it out to cover costsRinse, repeat. Soon I will own infinite properties with tons of rental income! My guess is that this doesnt work in general for the entire population because of finite resources. So, applying quasi-reasoning hence the hunch, a reverse mathematical induction would tell me that owning any property is unprofitable. If owning and renting out even one property made financial sense, everyone would be landlords. In reality this is not the case.So, I have circumstantial evidence to suggest that: rental income - mortgage payment - maintenance cost - taxes 0is not enough of a reason to own infinite properties. Is there reason this might be the case?  <response>: Take out mortgageHeres your problem - this is not a given. You dont take out a mortgage - a bank agrees to give you one... or not. Since your outstanding debt factors into whether you will be approved for a mortgage or not, you wont be able to take out mortgages on large numbers of properties. 