In Arizona, legal malpractice claims are generally governed by the statute of limitations for tort claims in A.R.S. § 12-542, which provides that such claims must be brought "within two years after the cause of action accrues." See Kiley v. Jennings, Strouss & Salmon, 187 Ariz. 136, 139, 927 P.2d 796, 799 (App. 1996).
Arizona applies the discovery rule to determine when a cause of action for legal malpractice accrues. Commercial Union Ins. Co. v. Lewis & Roca, 183 Ariz. 250, 254, 902 P.2d 1354, 1358 (App. 1995).
"The discovery rule applies not only to the discovery of negligence, but also to discovery of causation and damage." Id. at 253, 902 P.2d at 1357.
Thus, for legal malpractice claims, the limitations period starts to run when the client has suffered harm and knows or should have known that the harm was a direct result of the attorney's negligence. Id.