State v. Nelson (2012)
In State v. Nelson, 229 Ariz. 180,22, 273 P.3d 632, 638 (2012), the court reviewed such an instruction for fundamental error when evidence showed the defendant had left the scene, walked to a store, bought the murder weapon, walked back to the scene, and murdered the victim. 229 Ariz. 180,22-23, 273 P.3d at 638.
The court found no error, and did not indicate that the length of time involved dictated whether the last sentence was necessary. Id.23.
Nelson concerns a potentially long period in which the defendant left to purchase a weapon, Nelson, 229 Ariz. 180,23, 273 P.3d at 638.