Background.  A  suit on sworn account is not actually a separate independent cause of  action, but rather is a procedural tool based on Rule 185 of the Texas  Rules of Civil Procdure that limits the evidence necessary to establish a prima facie right to recovery against a person or entity who defaults on certain types of accounts. Williams v. Unifund CCR Partners Assignee of Citibank, 264 S.W.3d 231, 234 (Tex. App.--Houston [1st Dist.] 2008, no pet.); see Tex. R. Civ. P. 185.  In any action founded upon an open account or claim for goods,  including a claim for a liquidated money demand based upon written  contract, the account is prima facie evidence that a claim for the  amount is owed if a systematic record has been kept and the record is  supported by an affidavit. Tex. R. Civ. P. 185. A defendant must rebut a  sworn account with a sworn denial. Id.; Tex. R. Civ. P. 93(10); Canter v. Easley, 787 S.W.2d 72, 73 (Tex. App.--Houston [1st Dist.] 1990, writ denied); see also Huddleston v. Case Power & Equip. Co., 748 S.W.2d 102, 103-04 (Tex. App.--Dallas 1988, no writ) (holding that sworn general denial is insufficient).

Elements.  To  prevail against a sworn denial, a plaintiff must show: (1) the sale and  delivery of merchandise; (2) the amount owed is just, that is, in  accordance with an agreement, or if there is no agreement, the prices  are the usual, customary and reasonable prices for that merchandise; and  (3) the amount is unpaid. Worley v. Butler, 809 S.W.2d 242,  245 (Tex. App.--Corpus Christi 1990, no writ).  If these pleading  requirements are met, and the opposing party fails to file a verified  denial, the petition and affidavit are prima facie evidence of a sworn  account. Tex. R. Civ. P. 185.

Statute of Limitations.  The four year statute of limitations applies to a breach of contract / sworn account claim. Stine v. Stewart, 80 S.W.3d 596, 592 (Tex. 2002).  A party asserting the claim must sue no more than four years after the claim accrues. Id. A breach of contract claim accrues when the contract is breached. Id. Typically, in a sworn account situation, the breach is when the  defendant fails to pay the amount due. If the matter involves an open  account, the plaintiff's claim may not accrue until the cessation of  dealings between the parties. See Capital One Bank (USA), N.A. v. Conti,  345 S.W.3d 490, 491 (Tex. App. - San Antonio 2011, no pet.). The  elements of an open account are: (1) transactions between the parties;  (2) creating a creditor-debtor relationship through the general course  of dealing, (3) with the account still being open, and (4) with the  expectation of further dealing. Capital One Bank (USA), N.A.,  345 S.W.3d at 491. Unless an open account situation applies, a plaintiff  needs to bring suit on a sworn account within four years from the failure of the defendant to pay the due account.