With one duplex you should be focused on selling 99.9% of the time and .1% on the duplex.

I think about this often, its really just running the numbers - if you borrow 100k at an 8% interest rate, will the investment get you more than an 8% return?

I was then told that's the rate for the area.

Little did I know it would take decades to ripen :)3. bought a foreclosure sale .. traded the house for the 3 acres the person who owned the house. 

The asking price was 125,000 and after I did a walkthrough with my agent I offered 100,000 because the house needed some serious work done.

The median home value in Phoenix as of April 2023 was $368,657, which is a 23.5% increase from the previous year. 

Good luck with the wholesaling strategy.

With the current market conditions, I can definitely see more of these type properties becoming available in the future.

The one aspect I'd say where planning can really provide benefit however is with tax planning.  

Quote from @Dennis McNeely: In a sandwich lease option, the investor exercises their option with the property owner to purchase the property when the tenant-buyer indicates they're ready to exercise their option and purchases the property.