Section 18.001 et seq. of the Texas Civil Practice & Remedies Code was enacted to allow for a prima facie showing of the necessity and reasonableness of services by affidavit rather than expert testimony. This evidentiary procedural rule provided plaintiffs with the ability to streamline the necessary proof to establish the reasonableness and necessity of costs. See Gunn v. McCoy, 554 S.W.3d 645, 672 (Tex. 2018) (“Generally speaking, section 18.001 is ‘purely procedural, providing for the use of affidavits to streamline proof of the reasonableness and necessity of medical expenses.’”) (quoting Haygood v. De Escabedo, 356 S.W.3d 390, 397 (Tex. 2011)). If left uncontroverted, the affidavits under Section 18.001 were sufficient proof to support a plaintiff’s claims. However, if properly controverted under that Rule, the affidavits are precluded from being used as evidence of reasonableness and necessity, and plaintiffs are required to prove up the reasonableness and necessity of services by expert testimony at trial. See Wal-Mart Stores Tex., LLC v. Bishop, 553 S.W.3d 648, 672 (Tex. App.–Dallas 2018).

Typically, this Rule has been used in personal injury cases to prove up the reasonableness and necessity of medical expenses. However, the Rule itself is not so narrow, providing that it “applies to civil actions only, but not to an action on a sworn account.” Tex. Civ. Prac. & Rem. Code § 18.001(a). In fact, plaintiffs have used Chapter 18 affidavits to prove up the reasonableness and necessity of a number of things, including attorneys’ fees, engineering and consulting fees, and vehicle repairs. See, e.g., Day v. Federation of State Med. Bds of the U.S., Inc., 579 S.W.3d 810 (Tex. App.–San Antonio 2019) (attorney’s fees); Manon v. Tejas Toyota, Inc., 162 S.W.3d 743, 751 (Tex. App.–Houston [14th Dist.] 2005) (attorney’s fees); D & M Marine, Inc. v. Turner, 409 S.W.3d 693 (Tex. App.–Houston [1st Dist.] 2013) (engineering and consulting fees); McFarland v. Am. Multicinema Corp., 1996 WL 38070 (Tex. App.–Houston [1st Dist.] 1996) (vehicle repairs).Ostensibly, these affidavits could be used any time a party needs to establish the reasonableness or necessity of services in a civil action, and practitioners should be diligent in calendaring counteraffidavit deadlines if they see one to prevent their admission as prima facie evidence.