C'mon everyone, let's be realistic about this. Most of us don't have the discipline to pay cash for your investment properties, because it would take a long time to acquire properties. Most of us end up borrowing money, because we are so excited to jump into the property investment market that we're willing to take on enormous risk.
Dave Ramsey's plan if you don't know is that his strategy is to pay cash for your rental properties by saving as much money as you can and living on beans and rice. The first property could take 3-5 years. The second might do the same. So after 10 years you may have 3 properties owned clear and free. The more property you have mortgage free your able to multiply your savings X?. So for example if you have 3 duplex's and after all expenses your clearing $1,500 each month, that's $4,500. $4,500 X 12 months = $54,000. Take that amount plus whatever disposable cash you may have and you can add a fourth mortgage free property. Keep doing this and you could have 10 paid for properties in 20 years easily.
So don't discount Dave's strategy. I just don't believe most people have the patience.
I'm more of an in between type investor, where I put 20% to 25% on my properties with cash reserves for EF's.