If they purchase, the option fee amount paid will be reduced from the purchase price to lower the purchase price on the sales agreement, after they exercise their option to purchase.* The property is not sold and title is not transferred until the tenant exercises the option to buy.

The non-refundable lease option fee IS applied to the purchase if the optionee exercises the option.It looks as though your realtor friend proposed a seller-financed deal.  

If what she is saying is true then she can exercise her option to purchase whenever she gets her windfall.

Buyer exercises option.

If you buy a property that clearly you can add value to (i.e renovate interiors, exteriors, perhaps add a carport that you can charge parking fees on, retrofit plumbing to save on utilities, etc) you can exercise more control over creating value.  

He's making 4% on a passive instrument and has given up the hassles of active ownership.Note  buying is a popular exercise because it's a passive way to still invest in real estate for the long term backed by a real estate asset.  

But it is still good to go through the exercise of the analysis.  

If a washer and dryer are included in the lease, then the landlord is in default and the tenant can exercise whatever remedies are provided by the laws of that state.

What is average length of time you give someone to exercise their option?

Do you have any "practice exercises" you would suggest so that one can get really comfortable analyzing and running numbers?