Two flips side by side complicates this because you can only claim one as your primary at a time.The scenario you're describing -- live in the first, then move to the second to reset the clock -- works mathematically but it's slow.

The American Dream of homeownership is currently hitting a mathematical wall.

At that point the properties function more like income assets than growth assets, and the cash flow could then be used to fund future investments or lifestyle flexibility.I realize this may not be the mathematically “optimal” strategy compared to continuous leverage and scaling, but I’m interested in hearing from people who value cash flow stability and lower debt exposure.Has anyone here actually taken this kind of approach or something different?

I will disagree, although usually we're on the same page.Whether you apply 100% bonus depreciation to appliances or deduct it as repair produces the exact same mathematical result in the first year. 

Many owners believe holding out for a higher rent is the smart move.In reality, waiting can be more expensive than lowering the price.The Cost of VacancyLet’s look at a simple example.You want $2,000/month, but the market is telling you $1,900.You decide to wait.If the property sits vacant for:1 month → you lose $2,0002 months → you lose $4,000Now let’s amortize that loss over a standard 12-month lease.If you dropped the rent by $100/month:$100 × 12 months = $1,200 total differenceCompare that to:$2,000–$4,000 in lost income from vacancyWaiting for the “right” number just cost you more than accepting the market rate.Vacancy Is the Silent Cash Flow KillerVacant properties don’t just lose rent — they still have:Mortgage paymentsTaxesInsuranceUtilitiesMaintenance riskA slightly lower rent with consistent occupancy almost always outperforms a higher rent with prolonged vacancy.Running the Numbers Changes the MindsetWhen you truly run your numbers — not emotionally, but mathematically — you start asking better questions:How long can I afford this property to sit empty?

I do like how @Joe Villeneuve gave a mathematical way to analyze it.

Furthermore, expecting a turnkey 3-4 unit to produce pure positive cash flow while using a low-down-payment conventional loan is mathematically near-impossible right now because the heavy debt service of a 5% down loan eats up your margins.

Mathematically, the metric that captures that tradeoff is Total Return on Equity, not just CoC. 

It can solve mathematical problems that would take conventional super computers billions upon billions of years, and do it in seconds. 

A down payment is a cash flow (out).Mathematically yes, but psychologically not the same and risk timing matters.