Mertola LLC v. Alberto santos/arlene Santos, 422 P.3d 1028

Santos obtained a Washington Mutual credit card with a $25,000 limit governed by an Account Agreement that allowed the lender to optionally "declare [the] Account balance immediately due and payable" on default and waived notice of acceleration.
From Aug 2007–Jan 2008 Santos made late minimum payments; he missed the February 2008 payment and thereafter made no full minimum payments (a $50 payment in Aug 2008 did not cure default).
The Bank charged off the account in 2008 with a $17,066.91 unpaid balance; Mertola later acquired the debt and sued on July 18, 2014 for the entire outstanding balance.
Santos moved for summary judgment, arguing the six-year statute of limitations under A.R.S. § 12-548(A)(2) barred Mertola because the claim accrued at the first uncured missed payment in Feb 2008.
The superior court granted summary judgment for Santos; the court of appeals reversed, holding accrual of the full-balance claim required notice or demand of acceleration; the Supreme Court granted review.
The Supreme Court held that for credit-card accounts with optional acceleration, the cause of action for the entire debt accrues at the first uncured missed minimum payment (default), so Mertola’s suit was time-barred.

Issue	Plaintiff's Argument	Defendant's Argument	Held
When does the cause of action to recover the entire credit‑card balance accrue under an optional acceleration clause?	Accrual occurs only when the creditor manifests acceleration (demand or notice); missed payments permit suit only for those installments.	Accrual occurs at the first uncured missed minimum payment (default); creditor need not accelerate to start the limitations period.	The Court held accrual for the entire balance occurs at the first uncured missed minimum payment; Mertola’s claim was barred by the six‑year statute.

Gust, Rosenfeld & Henderson v. Prudential Ins. Co. of Am., 182 Ariz. 586 (1995) (general rule: cause of action accrues when a party can sue)
Johnson v. Johnson, 195 Ariz. 389 (App. 1999) (statute of limitations runs on each installment when due for traditional installment debts)
Navy Fed. Credit Union v. Jones, 187 Ariz. 493 (App. 1996) (for closed-end installment notes, full-balance accrual may await exercise of acceleration)
Baseline Fin. Servs. v. Madison, 229 Ariz. 543 (App. 2012) (reaffirmed Navy Federal and required affirmative act evidencing acceleration for closed-account debts)
Browne v. Nowlin, 117 Ariz. 73 (1977) (acceleration clauses protect lenders; debtor may cure default and thereby defeat pending cause of action)