The Single Biggest Mistake I See
The single biggest first-deal mistake I see in coaching self storage acquisitions: a new buyer takes the seller's P&L at face value, plugs it into a model, and prices a deal off numbers that were optimized to make the buyer overpay.
Sellers don't typically lie on a P&L. They omit. They reclassify. They use unrealistic categories. They show what they want you to see.
Here's the line-by-line breakdown of where storage sellers most commonly manipulate the P&L.
Line 1: Gross Potential Revenue (GPR).
What you'll see: a number that assumes 100% occupancy at current asking rates with zero delinquency.
What's manipulated: the "asking rates" in the GPR are often the rates listed on the website, not the rates actually being collected. If 60% of the unit mix is rented at $80 and the listed rate is $110, the seller's GPR uses $110 across the board.
What "real" looks like: pull the rent roll. Calculate the actual weighted-average rate per unit type. Multiply by total units. That's the real GPR. It's typically 10-25% below the seller's GPR.
Line 2: Vacancy and Bad Debt.
What you'll see: a single combined line that says something like "Vacancy & Collections: 5%."
What's manipulated: it conflates physical vacancy (units not rented) with economic vacancy (units rented but not collecting full rent due to discounts, free months, or delinquency). Real economic vacancy on a "fully occupied" mom-and-pop facility is often 10-15% when delinquency is counted.
What "real" looks like: pull the most recent 12-month collection history. Calculate (Collected Revenue ÷ Gross Potential Revenue) — that's your real economic occupancy.
Line 3: Management Fees / Payroll.
What you'll see: $0 or "owner-managed" or a fee that's dramatically below industry standard.
What's manipulated: owner-operators don't pay themselves a real wage and don't book the value of their own time.
What "real" looks like: assume 6-8% of gross revenue for third-party property management, OR allocate your own time at $50-100/hour. A facility making "$80K NOI" with the owner pretending he/she does the work for free is closer to a $65K NOI facility if you allocate the real cost. That's a 19% NOI haircut. Translated to a cap-rate purchase decision: the seller's 8-cap is your 6.5-cap.
Line 4: Insurance.
What you'll see: an insurance line that hasn't been updated in 2-3 years.
What's manipulated: insurance premiums have climbed 30-50% across most commercial real estate categories from 2022-2026 due to reinsurance market dynamics.
What "real" looks like: get a binding quote from your own commercial broker before you finalize the model.
Line 5: Property Taxes.
What you'll see: the current property tax bill, which reflects the assessed value when the SELLER owned the property.
What's manipulated: in most states, the assessed value resets to the SALE PRICE the year after the transaction closes (tax reassessment on sale). If the seller bought 8 years ago at $300K and is selling to you at $900K, your post-acquisition property tax bill could be 2-3x the seller's current bill.
What "real" looks like: call the county assessor. Ask about post-sale reassessment timing and methodology. Underwrite the post-reassessment number.
In some markets, the post-reassessment property tax line item alone moves the cap rate by 50-80 basis points.
Line 6: Repairs and Maintenance.
What you'll see: a low R&M line - often $2,000-5,000 per year on a small facility.
What's manipulated: the seller has deferred capex they're not booking. The roof needs $30K of work. The fencing needs $8K. The gate motor is one storm from failing. The seller hasn't fixed any of it, so the R&M line looks lean.
What "real" looks like: budget at least 4-7% of gross revenue for ongoing R&M (industry baseline), and separately model the year-one capex bucket from your own walk-through inspection.
Line 7: "Other" / Miscellaneous Income.
What you'll see: an "Other Income" line that includes one-time items, parking fees, RV/boat outdoor storage, U-Haul rentals, late fees, lock sales, tenant insurance, and anything else the seller wants to inflate.
What's manipulated: one-time items get included as if they're recurring. Tenant insurance might be booked at gross premium received without backing out the actual insurance company's cut.
What "real" looks like: decompose the line. Recurring items stay. One-time items come out.
The aggregate effect on the cap rate:
A typical seller's P&L on a small storage facility, run through these 7 adjustments, often produces a cap rate that's 100-200 basis points below the cap rate the seller is presenting.
A "$1M, 8-cap" facility on the seller's numbers is often a $1M, 6-cap on adjusted numbers. The deal that looked great at face value is now a meh deal at the same price.
The framework I use:
When I receive an OM, I read the P&L once for the seller's narrative. Then I rebuild it from scratch:
→ GPR from the rent roll, not from the OM.
→ Economic occupancy from the collection history.
→ Management/payroll at real cost (or 6-8% of revenue).
→ Insurance from a current binding quote.
→ Property taxes from the post-reassessment number.
→ R&M at industry baseline + a separate year-one capex bucket.
→ "Other" income decomposed and conservative.
The strategic frame:
Reading a self-storage P&L is not a clerical skill. It's a contrarian skill. Most first-time buyers want to believe the seller's numbers because believing them justifies a faster decision.
The buyers who don't believe the seller's numbers — who do the work to rebuild the P&L from primary sources — are the buyers who don't lose money on their first deal.
The first P&L you rebuild from scratch will take you 6-8 hours. The tenth will take you 90 minutes. The compounding skill is worth more than any single deal.
If you've bought self-storage - what's the line item you wish you had scrutinized harder on your first deal?