Now you have some time buffer but still need to ensure that you can make the payouts for the second year. 

So, if it costs $200K to build a home, you should set aside $6K-$10K as a buffer.

I know we could use that cash for other things, but I like having the buffer.

There are so many assumptions built into their models around rent increases, minimal opex increases, and further compressed cap rates 5 years out, that there is little to no buffer in case anything goes wrong.If you are looking to invest in a syndication, look closely at these assumptions and compare them to the local market's demographics (population trends and job growth). 

The number of rentals that make you financially independent with huge buffer is enough. 

You could even take this a step further and say that commercial real estate would have greater margins/more price buffer.

Meaning no equity if there was a correction in the time you lived there to act as a buffer, and negative cashflow if you have to rent it out to avoid selling at a loss.

Vicky Robins mentions this in "YMOYL" - everyone's number starts at a million and just escalates from there, mostly because there's no real concrete idea what the money is needed for, so a very healthy buffer is required. 

I figure if I plan for 2-3X what I really think I will need, that gives me some buffer for something major.

Builders would build more units and developers would rehab old buildings.An increase in supply would most certainly buffer the demand.