This isn’t a rushed upgrade or a box-checking exercise.

Single-family tends to teach fundamentals like tenant management, financing, and cash flow discipline, while commercial forces you to think more about income, expenses, and structure.Since you already own a single-family home, even running numbers on it as a rental (realistic rent, expenses, taxes, reserves) can be a great learning exercise before jumping into the next deal.

Fortunately I have never had to exercise plan b.  

• Is it non-refundable consideration for the option itself,• credited/deducted from the future purchase price if the tenant exercises,• or refundable under certain conditions?

That's way too much exercising for me.I dunno, seems a bit risky to hold paper claiming to be a partial interest in a company and not understand what I'm doing. 

But this is a good thought exercise.  

But this was a good exercise and I ran some rough numbers and it appears to be around 10% So now that you see your paying as much as 10% of your profits to all the 3rd party apps does that make you second guess all these extra fees?

The mortgagee has a claim on the title that he can exercise by foreclosure on the mortgage. 

Beyond that, carrying - whether concealed or open - is mostly an exercise in machismo, since the vast majority of individuals that carry are men.

You want to exercise your right to check on the home which would include an interior walkthrough to make sure there are no open valves or [potential hazards in the property.