The 7 Most Expensive Clause Mistakes in Commercial Leases

Over 15 years of CRE legal practice, certain provisions consistently appeared in dispute after dispute. Not because the attorneys were careless, but because the standard drafting approaches left dangerous ambiguity.

The Problem: "Tenant shall pay its pro rata share of operating expenses" seems clear until reconciliation time.

What Goes Wrong:

• Capital improvements: Included or excluded?
• Management fees: Capped or uncapped?
• Landlord's administrative costs: Which ones qualify?

The Fix: Explicit inclusions list, explicit exclusions list, cap structures where appropriate, and clear dispute resolution mechanisms. For more, see the complete guide to CAM reconciliation.

The Problem: "Rent shall increase by CPI annually" doesn't specify:

• Which CPI index (there are multiple)
• The measurement period
• Floor and ceiling caps
• What happens if the index is discontinued

Real Consequence: A client faced $47,000 in disputed rent over a 10-year term because the lease didn't specify the CPI measurement methodology. The rent escalation guide covers every method and what to specify, and you can verify numbers with the rent escalation calculator.

The Problem: "Landlord shall respond within a reasonable time" is unenforceable.

What "Reasonable" Means in Court: Whatever the judge thinks it means that day.

The Fix: Every obligation needs a specific timeline. Every timeline needs a consequence for breach. And every deadline needs to be tracked, because even perfectly drafted deadlines cost millions when they're missed.

The Problem: "If the anchor tenant closes, Tenant may reduce rent by 50%."

What's Missing:

• What counts as "closes"? Temporarily? Permanently?
• Does subletting count?
• What about reduced hours?
• How long must the condition persist before remedies kick in?

The Problem: Poorly drafted assignment provisions can give landlords an unintended termination right, or give tenants an unintended escape.

Common Gap: "Landlord may withhold consent to assignment in its sole discretion" interacting with "Landlord shall respond within 30 days; failure to respond constitutes approval."

The Problem: "Tenant responsible for routine maintenance; Landlord responsible for structural repairs."

The Litigation Question: Is HVAC replacement routine or structural? What about roof repairs that started routine and became major?

The Problem: "Renewal rent shall be fair market value as of the renewal date."

What's Missing:

• Who determines FMV?
• What comparable properties are considered?
• What's the dispute resolution if parties disagree?
• Is there a floor or ceiling?

Real Consequence: A client spent $85,000 in arbitration costs over a renewal rent dispute that could have been avoided with a clear determination methodology. See the full guide on options, ROFO, and ROFR provisions for how to draft these correctly.

Each of these mistakes happens in documents drafted by capable attorneys. The problem isn't competence, it's that manual drafting under time pressure inevitably creates gaps. When your lease forms and deal logic are encoded into a structured drafting system, one that enforces completeness and flags internal inconsistencies, the most common errors get caught before they reach the first review.

• CAM Reconciliation: The Most Disputed Provision, a full breakdown of the #1 source of landlord-tenant disputes
• Rent Escalation Clauses: The Complete Guide, every escalation method, with calculation examples and drafting pitfalls
• Options, ROFO, and ROFR Provisions, the high-stakes provisions most frequently botched