They fall apart fast if they are not pushed through the banks' systems and all deadlines must be met promptly.  

Depending on the lead It can wear you out pretty quick try knocking in short spurts and follow up till you have a system down.  

I'm in the process of developing my business plan for the purpose of finding and acquiring buy and hold single family (possibly multi family), for the purposes of building a passive income stream in and around Houston...

@Andrew R. - This may help you some.

For example, things like a source of heat (furnace) in the wintertime, a working water heater, working plumbing/electrical systems, etc.

Then you can play around with what the system sends you. 

It's much easier to invest with confidence when you have a support system that you can utilize. 

I like this one for several reasons ... first, you can normally get a bigger discount buying all cash, Second, it matches the leverage against the risk profile, meaning that you are unleveraged in the beginning when you are learning and there are a lot of uncertainties with a distressed, unrented property, you then reduce this uncertainties with the 1st 3 R's before you leverage up.

As a vague, broad and more of a science fiction reference we have the sun that is continually putting inputs into our system and entire planets that are within reach that dwarf the resources that we have.

This answers so many questions I probably would have had in the future.If I could jump on and also ask a question:What is the best system for paying general contractors during a project?