As far as when to buy, it's tough to time the market perfectly since no one really knows what will happen in the future, as much as we try to predict it.

What is the best probability with which investor can predict crisis in given month? 

Housing Starts is a very good indicator, since 1965 it has never been wrong predicting a recession.

Looking at cash flow, in most cases it tends to be a more steady and predictable form of income as rents tend to fluctuate less and don't tend to drop off a cliff but rather will adjust slowly.

This is harder to predict in the volatile rate environment.

However, selling it did not work to accomplishing my goal......which was: Build a real estate portfolio that would provide substantial, predictable,  and sustainable income that would allow me to live a very high standard of living for the rest of my life.  

No one can predict the market and what it will do.

A multi-year lease is extremely beneficial for both the tenant and landlord.The goal for the tenant is to establish a valuable home for a predictable period of time.

I agree that some tenants might like the idea of having predictable heating costs which makes it easier to do their budgeting.

So when you know the highest is 6 you can stress test for years 6 to 10 and predict out cash flows somewhat.If you leave it open in year 6 to market that can be dangerous to do.I like floating rates or interest only rates more when a property is a value add and being turned around.