And also, know everything about operating real estate, if you really want to know the risks: business plan, financing structures, ability to execute, market research to vet their underwriting assumptions, how fees can influence investment decisions...3.

If they don't want to stay, they must give notice in writing and be out within 30 days.Give them a deadline to make the decision (one week is sufficient).

This would be an easy decision however I do not think you can come close even with you being active in the process.  

There are still other factors to analyze before making that decision.

Key Factors for a Good Seller-Financed DealCash Flow: Rental income should exceed monthly payments (PITI) by at least 1.25–1.5x.Purchase Price: Compare to ARV and market value for fair pricing and equity potential.Interest Rate: Aim for competitive rates; higher rates must still allow positive cash flow.Amortization/Balloon Terms: Favor longer amortization and align balloon payments with your exit strategy.Down Payment: Lower upfront costs reduce risk but should meet the seller's expectations.Flexibility: Seek no prepayment penalties and fair late-payment clauses.Property Condition: Ensure the property’s condition matches terms through inspections.Seller Motivation: Assess the seller’s willingness to negotiate favorable terms.Exit Strategy: Have a clear plan for refinancing or payoff at term end.Portfolio Fit: Ensure the deal aligns with your financial goals and risk tolerance.Vetting multiple deals and consulting professionals is crucial to making sound decisions.

We rely on these kinds of records to make decisions.

I appreciate the input and with think through this decision.

Most importantly, how can I set realistic, effective metrics to guide my investment decisions?

A turnover means repairs, painting, cleaning, marketing, vacancy time, and lost rent, so a small discount is often a better financial decision than churning tenants every year.There’s a lot more to consider, but these are some key lessons I’ve learned.

In my view they made the correct decision and if you spent significant time recovering this cost, well I think we all know what that is.