But be carefull, loans tend to multiply when you do not control your financial sutiation and you will have to take more and more to close previous ones and you will end with almost nothing but only debts.

Leverage just multiplies gains or losses.So, I'd say, if they're good properties and you anticipate gains then consider it regardless of age.

It’s a percent calculation of assessed land and property value multiplied by the purchase price.

Original cost (maybe per the appliance company previously mentioned)Multiplied by (11/estimated useful life).You absorb the rest.

I’ve come across he formula for dealing with Gross Rent Multiplier, which is the selling price of the property/gross rent per year. 

I don't currently have the capital so I'm spending my time educating myself and saving every dime and investing what I save to multiply it.

If there aren't comps there I personally would value the property relative to its potential rental income using either the gross rent multiplier or cap rate method. 

$280 a month multiplied by 12 is $3,380.Sometimes it's better/easier to see the gross number.

We have used this to grow some equity and then sell, get the gains tax free, and multiply the money using down-payments on a couple other rentals. 

I was able to put away about $30,000 in a single year saving every extra penny and living like a hermit, but that would have only bought me a class D house in the ghetto even here in Omaha.Leverage is not the enemy, it is a force multiplier and while I appreciate the success that one person had without leverage, we should not demonize it and act as though that way is somehow superior.