[Long Term] = [Monthly Rent] - ([Monthly Rent] * 0.50) - [Mortgage Payment] - [HOA Misc]

Long Term Cash Flow is like the 15% rule only much more pessimistic. In the very long term, you may need to replace a roof, renovate a kitchen and account for a vacancy. While not necessary, if you are positive here you can weather most any storm and still make money. Formula: 50% of monthly Rent minus the monthly Mortgage Payment.