So here's another question then. Say I can get a 15 y/o house that is ready to rent, nothing needs immediate attention for 100k. 30 year deal, 6%, P&I is 600, say I can rent it for 1300. Using the 50% rule, I get:
1300 monthly income - 600 P&I - 600 expenses = 100 cash flow.
Same exact house, same exact price, but it's brand new. Equation is the same - on paper, I am looking at the same deal. But, with the older house, I am looking at a new roof in 5-15 years, water heater and HVAC work any time, etc. In the new house, I've probably got 10 years of runway where expenses are way less than 600 per month, I can save that money for future expenses.
How do I account for the value of new or relatively new construction vs. older construction? In my area, there are a lot of 100 year old homes, a lot of 10 year old homes, and some 2 year old homes for sale. Is there a way to modify the 50% rule of thumb to account for this?