So if this is a neighborhood of properties then the value should be pretty stable.  

In our case my wife and I are both retired, our properties are paid for and we are making more money than we need.

@Philip Marzen The book by Chad Carson called "Retire Early with Real Estate" touches on this subject a bit!

With 15 it's paid off faster and some use that as a plan for retirement. 

Sometimes if investors are nearing retirement and liquidating their portfolio, then seller financing is a good option for them as it allows them to spread their capital gains taxes over multiple years and it allows them to keep making money on the property via interest.

But you can invest in a 506(b) along with other IRA investors that may lack the knowledge to perform adequate due diligence.To me, this is starting to look like black market investing for your retirement. 

While she has little to contribute financially, I will be providing the financing, she has half interest in our primary residence that is worth about $250,000 and is income producing, and $35,000 in retirement funds for assets.

Sophia, my wife, and I have developed a plan of attack for acquiring rental homes in the primary and secondary markets based on where we want to retire.

He retired to Florida, bought a home with proceeds of the business sale, and was protected by the FL homestead law.

I'm 54 and retired and this could get me nicely to 59 and 1/2.