Professor Jessie

The Rent-vs-Buy Truth Serum

"A house is the best investment you'll ever make" is a slogan, not an analysis. It's repeated by real estate agents, parents, and television personalities — but it's rarely backed by actual math. The honest comparison between renting and buying requires identifying which costs are unrecoverable — money that builds no equity and is gone forever — and comparing them head to head.

The Unrecoverable Costs of Owning

When you own, a surprising share of your monthly housing spending disappears forever — it doesn't build equity, doesn't grow your net worth, and can't be recovered at sale:

• Mortgage interest — Front-loaded by amortization (see below); in the early years, 80%+ of your payment is interest
• Property taxes — Typically 1-2% of home value per year, every year, forever
• Insurance — ~0.5% of home value per year
• Maintenance & repairs — Budget 1-2% of home value per year, every year. This is lumpy (roof: $12k, HVAC: $8k) but it averages out
• Transaction costs — Buying costs 2-5% (closing, inspection, appraisal); selling costs 6-8% (agent commissions dominate)
• HOA fees — Where applicable, often $200-500/month with annual increases

The Unrecoverable Cost of Renting

Rent. That's it. Your rent check is the only money that disappears. Every other dollar you don't spend on housing can be invested and compound in your favor.

The Price-to-Rent Heuristic

A quick screening tool: divide the home price by the annual rent of an equivalent home.

Example: A $420,000 home vs. $2,000/month rent ($24,000/year). Ratio = 420,000 ÷ 24,000 = 17.5 — gray zone, full analysis required.

Anatomy of a Mortgage: PITI

Your monthly mortgage payment is not just principal and interest. The full PITI breakdown includes:

The PITI payment is what you actually owe each month — not the "P&I" number the real estate listing quotes to make it look affordable. Always calculate all-in costs before falling in love with a property.

Amortization: The Bank Gets Paid First

Mortgage amortization is the same compounding formula from Week 11, applied at a 30-year scale — and it reveals a brutal truth about how banks structure loans. On a standard 30-year fixed mortgage, the early payments are overwhelmingly interest. The principal portion is tiny. This is by design: the bank front-loads its profit so that refinancing or selling early still leaves them well-paid.

$320,000 Loan at 6.5% Fixed, 30 Years

Monthly P&I = $2,022. Here's where that money goes at different points in the loan:

Total paid over 30 years: ~$728,000. Total interest: ~$408,000 — that's 128% of what you borrowed. You paid for the house twice.

Same loan at 15 years: payment jumps to ~$2,800/month, but total interest drops to ~$184,000 — a savings of $224,000. The question is whether you can afford the higher payment and whether investing the difference elsewhere would earn more.

Choosing Your Loan Structure

15-Year vs. 30-Year Fixed

Mortgage Points: Prepaid Interest

Points are upfront fees that buy down your interest rate — essentially prepaid interest. One point typically costs 1% of the loan amount and reduces the rate by ~0.25%. Whether they make sense depends entirely on your break-even horizon: how many months of lower payments until you recoup the upfront cost.

Example: Paying $3,200 (1 point on a $320k loan) to reduce your rate from 6.5% to 6.25% saves ~$52/month. Break-even: $3,200 ÷ $52 = ~62 months (~5.2 years). If you'll stay past 5.2 years, points pay off. If you might sell sooner, skip them.

Adjustable-Rate Mortgages (ARMs)

ARMs offer a lower initial rate that resets after a fixed period (typically 5, 7, or 10 years). They're tempting when rates are high — but they carry interest rate risk. If rates rise further when the ARM resets, your payment can jump dramatically. ARMs make sense in narrow situations: you're certain you'll sell or refinance before the reset, or you expect rates to fall. For most primary-residence buyers planning to stay long-term, fixed-rate mortgages eliminate a risk you don't need to take.

Affordability: What the Bank Says vs. What You Can Afford

A pre-approval letter tells you the maximum the bank will lend you. It is not a recommendation — it's a sales target. The bank profits from a larger loan. Your job is to determine what you can actually afford while maintaining your other financial goals.

The house-poor trap — a beautiful house with empty investment accounts, one layoff from disaster — is the most common financial mistake among first-time homebuyers. The bank approved the loan; they didn't approve a life.

The Buying Sequence (Do This in Order)

• 1. Emergency fund full + investing waterfall running (Weeks 4 & 12) — before saving a down payment
• 2. Down payment in safe vehicles only (HYSA or short-term T-bills — never stocks or crypto for money needed within 3 years)
• 3. Credit score 760+ (Week 5 work pays ~0.5% on the rate — tens of thousands over the loan)
• 4. Rate-shop 3+ lenders within the 14-45 day window (counts as a single credit inquiry)
• 5. 20% down, ≤ 25% of take-home, 7+ year horizon, inspection always

Ownership Economics Beyond the Mortgage

Maintenance Reality

The 1% per year rule means a $400,000 home needs ~$4,000/year in maintenance — averaged over time. But maintenance is lumpy, not smooth: a roof replacement is $12,000, an HVAC system is $8,000, a water heater is $1,500. Some years you spend almost nothing; other years you spend $20,000. This is a sinking fund (from Week 3), not a surprise. Set aside money monthly even when nothing breaks.

Tax Treatment

Mortgage interest is deductible only if you itemize deductions. After the 2017 tax law changes raised the standard deduction significantly, most homeowners no longer benefit from itemizing — run your actual numbers. However, the capital gains exclusion on a primary residence is one of the best free lunches in the tax code: $250,000 for singles, $500,000 for married couples, tax-free, if you lived in the home for 2 of the last 5 years. That's potentially half a million dollars of gains with zero capital gains tax.

Equity Is Not Liquid

A paid-off house produces no cash flow. You can't buy groceries with home equity. HELOCs and cash-out refinances convert equity to debt — useful tools, but not income. In retirement planning, treat home equity as a reserve accessed via downsizing, not as an ATM. The wealthiest retirees often have a paid-off home and a substantial investment portfolio — the house is the safety net, the portfolio is the income.

Practical Exercise: Your Housing Analysis

Four Drills for Your Real Market

• 1. Rent-vs-buy for your city: Pick a real listing and a comparable rental. Compute the price-to-rent ratio. Build the full 10-year comparison: total unrecoverable costs of each option, assuming 3% home appreciation, 3% rent inflation, and investing the down payment at 8% if you rent.
• 2. Amortization drill: For the listing's price with 20% down at current 30-year rates: compute monthly PITI (estimate taxes and insurance), the payment-1 interest/principal split, and total 30-year interest. Then compute the same at 15 years. Write both totals side by side.
• 3. Affordability ceiling: Using your actual take-home pay, compute your max all-in housing payment (25% of take-home) and back into a max home price at current rates.
• 4. Readiness checklist: Score yourself on the buying sequence — emergency fund full? Credit score 760+? Timeline 7+ years? Down payment saved in safe vehicles?

Key Takeaways

• "Best investment you'll make" is a slogan, not analysis — compare unrecoverable costs head to head
• Price-to-rent ratio: below 15 = buy, above 20 = rent + invest the difference, 15-20 = run the numbers
• PITI (Principal, Interest, Taxes, Insurance) is the real monthly cost — not the P&I the listing quotes
• Amortization front-loads interest — your first payment is ~86% interest, building almost no equity
• $320k at 6.5% over 30 years = ~$408k in interest (128% of the loan) — the 15-year saves ~$224k
• Affordability ceiling: ≤ 25% of take-home pay, all-in — not the bank's 28-36% of gross
• 20% down eliminates PMI; 3-3.5% down is allowed but costly over time
• The $250k/$500k primary-residence capital gains exclusion is one of the tax code's best free lunches
• Home equity is illiquid — treat it as a reserve, not an ATM
• A 30-year fixed mortgage is one of the few debts worth carrying — the bank bears inflation risk